1Q TWENTY23 INVESTOR PRESENTATION ORIGIN BANCORP, INC.

2 FORWARD-LOOKING STATEMENTS AND NON-GAAP MEASURES This presentation contains certain forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Forward-looking statements include information regarding Origin Bancorp, Inc.'s ("Origin" or the "Company") future financial performance, business and growth strategy, projected plans and objectives, and any expected purchases of its outstanding common stock, and related transactions and other projections based on macroeconomic and industry trends, changes to interest rates by the Federal Reserve and the resulting impact on Origin's results of operations, estimated forbearance amounts and expectations regarding the Company's liquidity, including in connection with advances obtained from the FHLB, which are all subject to change and may be inherently unreliable due to the multiple factors that impact broader economic and industry trends, and any such changes may be material. Such forward-looking statements are based on various facts and derived utilizing important assumptions and current expectations, estimates and projections about Origin and its subsidiaries, any of which may change over time and some of which may be beyond Origin's control. Statements or statistics preceded by, followed by or that otherwise include the words "assumes," "anticipates," "believes," "estimates," "expects," “foresees,” "intends," "plans," "projects," and similar expressions or future or conditional verbs such as "could," "may," “might,” "should," "will," and "would" and variations of such terms are generally forward-looking in nature and not historical facts, although not all forward-looking statements include the foregoing words. Further, certain factors that could affect the Company's future results and cause actual results to differ materially from those expressed in the forward-looking statements include, but are not limited to: potential impacts of the recent adverse developments in the banking industry highlighted by high-profile bank failures, including impacts on customer confidence, deposit outflows, liquidity and the regulatory response thererto, the impact of current and future economic conditions generally and in the financial services industry, nationally and within Origin’s primary market areas, including the effects of declines in the real estate market, high unemployment rates, inflationary pressures, elevated interest rates and slowdowns in economic growth, as well as the financial stress on borrowers and changes to customer and client behavior as a result of the foregoing, deterioration of Origin's asset quality; factors that can impact the performance of Origin's loan portfolio, including real estate values and liquidity in Origin's primary market areas; the financial health of Origin's commercial borrowers and the success of construction projects that Origin finances; changes in the value of collateral securing Origin's loans; developments in our mortgage banking business, including loan modifications, general demand, and the effects of judicial or regulatory requirements or guidance; Origin's ability to anticipate interest rate changes and manage interest rate risk (including the impact of higher interest rates on macroeconomic conditions, competition, and the cost of doing business); the effectiveness of Origin's risk management framework and quantitative models; Origin's inability to receive dividends from Origin Bank and to service debt, pay dividends to Origin's common stockholders, repurchase Origin's shares of common stock and satisfy obligations as they become due; the impact of labor pressures; changes in Origin's operation or expansion strategy or Origin's ability to prudently manage its growth and execute its strategy; changes in management personnel; Origin's ability to maintain important customer relationships, reputation or otherwise avoid liquidity risks; increasing costs as Origin grows deposits; operational risks associated with Origin's business; volatility and direction of market interest rates; significant turbulence or a disruption in the capital or financial markets and the effect of a fall in stock market prices on our investment securities; increased competition in the financial services industry, particularly from regional and national institutions, as well as from fintech companies, difficult market conditions and unfavorable economic trends in the United States generally, and particularly in the market areas in which Origin operates and in which its loans are concentrated; an increase in unemployment levels and slowdowns in economic growth; Origin's level of nonperforming assets and the costs associated with resolving any problem loans including litigation and other costs; the credit risk associated with the substantial amount of commercial real estate, construction and land development, and commercial loans in Origin's loan portfolio; changes in laws, rules, regulations, interpretations or policies relating to financial institutions, and potential expenses associated with complying with such regulations; periodic changes to the extensive body of accounting rules and best practices; further government intervention in the U.S. financial system; a deterioration of the credit rating for U.S. long-term sovereign debt, actions that the U.S. government may take to avoid exceeding the debt ceiling, or uncertainties surrounding the debt ceiling and the federal budget; compliance with governmental and regulatory requirements, including the Dodd-Frank Wall Street Reform and Consumer Protection Act and others relating to banking, consumer protection, securities, and tax matters; Origin's ability to comply with applicable capital and liquidity requirements, including its ability to generate liquidity internally or raise capital on favorable terms, including continued access to the debt and equity capital markets; changes in the utility of Origin's non-GAAP liquidity measurements and its underlying assumptions or estimates; uncertainty regarding the transition away from the London Interbank Offered Rate ("LIBOR") and the impact of any replacement alternatives such as the Secured Overnight Financing Rate ("SOFR") on Origin's business; possible changes in trade, monetary, and fiscal policies, laws, and regulations and other activities of governments, agencies and similar organizations; natural disasters and adverse weather events, acts of terrorism, an outbreak of hostilities (including the impacts related to or resulting from Russia's military action in Ukraine, including the imposition of additional sanctions and export controls, as well as the broader impacts to financial markets and the global macroeconomic and geopolitical environments), regional or national protests and civil unrest (including any resulting branch closures or property damage), widespread illness or public health outbreaks or other international or domestic calamities, and other matters beyond Origin's control; and system failures, cybersecurity threats and/or security breaches and the cost of defending against them. For a discussion of these and other risks that may cause actual results to differ from expectations, please refer to the sections titled "Cautionary Note Regarding Forward-Looking Statements" and "Risk Factors" in Origin's most recent Annual Report on Form 10-K filed with the Securities and Exchange Commission ("SEC") and any updates to those sections set forth in Origin's subsequent Quarterly Reports on Form 10-Q and Current Reports on Form 8-K. If one or more events related to these or other risks or uncertainties materialize, or if Origin's underlying assumptions prove to be incorrect, actual results may differ materially from what Origin anticipates. Accordingly, you should not place undue reliance on any forward-looking statements. Any forward-looking statement speaks only as of the date on which it is made, and Origin does not undertake any obligation to publicly update or review any forward-looking statement, whether as a result of new information, future developments, or otherwise. New risks and uncertainties arise from time to time, and it is not possible for Origin to predict those events or how they may affect Origin. In addition, Origin cannot assess the impact of each factor on Origin's business or the extent to which any factor, or combination of factors, may cause actual results to differ materially from those contained in any forward-looking statements. All forward-looking statements, expressed or implied, included in this communication are expressly qualified in their entirety by this cautionary statement. This cautionary statement should also be considered in connection with any subsequent written or oral forward-looking statements that Origin or persons acting on Origin's behalf may issue. Annualized, pro forma, adjusted projected and estimated numbers are used for illustrative purposes only, are not forecasts, and may not reflect actual results. Certain prior period amounts have been reclassified to conform to the current year financial statement presentations. These reclassifications did not impact previously reported net income or comprehensive income. Origin reports its results in accordance with United States generally accepted accounting principles ("GAAP"). However, management believes that certain supplemental non-GAAP financial measures may provide meaningful information to investors that is useful in understanding Origin's results of operations and underlying trends in its business. However, non-GAAP financial measures are supplemental and should be viewed in addition to, and not as an alternative for, Origin's reported results prepared in accordance with GAAP. The following are the non-GAAP measures used in this presentation: adjusted net income, adjusted PTPP earnings, adjusted diluted EPS, NIM-FTE, adjusted, adjusted ROAA, adjusted PTPP ROAA, adjusted ROAE, adjusted PTPP ROAE, tangible book value per common share, adjusted tangible book value per common share, tangible common equity to tangible assets, ROATCE and adjusted ROATCE and adjusted efficiency ratio. Please see “Reconciliation of Non-GAAP Financial Measures” at the end of this presentation for reconciliations of non-GAAP measures to the most directly comparable financial measures calculated in accordance with GAAP.

ORIGIN BANCORP, INC. _______ 17 LOUISIANA Entry: 1912 Loans: $1,475 Deposits: $2,942 DOLLARS IN MILLIONS, UNAUDITED (1) (2) 3 ORIGIN COMPANY SNAPSHOT • Origin Bancorp, Inc. is the holding company for Origin Bank. • Origin Bank was founded in 1912 and is headquartered in Choudrant, LA. • 60 banking centers operating across Texas, Louisiana & Mississippi DEPOSITS & LOANS BY STATE Note: All financial information is as of 03/31/2023. * Please see slide 34 for all footnote references included above. MISSISSIPPI Entry: 2010 Loans: $610 Deposits: $689 9% 9% 38% 21% 53% 70% Loans (2)Deposits (1) ICS ICS 9 9 19 6 TEXAS Dallas/Fort Worth Houston East Texas Entry: 2008 Entry: 2013 Entry: 2022 Loans: $2,824 Loans: $1,754 Loans: $375 Deposits: $2,053 Deposits: $1,261 Deposits: $882 Total Texas Loans: $4,953 Total Texas Deposits: $4,196 ,

ORIGIN BANCORP, INC. _______ 4 A UNIQUE & DEFINED CULTURE

ORIGIN BANCORP, INC. _______ • Total deposits were $8.17 billion at March 31, 2023, reflecting an increase of $398.6 million, or 5.1%, compared to December 31, 2022. • LHFI to deposits, excluding mortgage warehouse lines of credit, was 86.1% at March 31, 2023, compared to 87.5% at December 31, 2022. • Cash and liquid securities as a percentage of total assets was 14.3% at March 31, 2023, compared to 12.1% at December 31, 2022. • The allowance for loan credit losses ("ALCL") to nonperforming LHFI was 538.75% at March 31, 2023, compared to 876.87% at December 31, 2022. • Tangible common equity to tangible assets(3) was 8.02% at March 31, 2023, compared to 8.11% at December 31, 2022. • March 31, 2023, Company level common equity Tier 1 capital to risk-weighted assets was 11.08%, Tier 1 leverage ratio was 9.79%, and the total capital ratio was 14.30%. Key Performance Metrics 1Q23 4Q22 Reported Adjusted Reported Adjusted B al an ce S he et Total Loans Held for Investment ("LHFI") $ 7,375,823 N/A $ 7,090,022 N/A Total Assets 10,358,516 N/A 9,686,067 N/A Total Deposits 8,174,310 N/A 7,775,702 N/A In co m e St at em en t Net Income $ 24,302 $ 24,188 $ 29,478 $ 30,409 Adjusted Pre-Tax, Pre-Provision ("adjusted PTPP") Earnings(3) N/A 36,627 N/A 42,103 Diluted EPS 0.79 0.78 0.95 0.99 Se le ct ed R at io s NIM - FTE 3.44 % 3.36 % (4) 3.81 % 3.73 % (4) Return on Average Assets (annualized) ("ROAA") 1.01 1.00 (3) 1.23 1.27 (3) Adjusted PTPP ROAA (annualized) N/A 1.52 (3) N/A 1.75 (3) Return on Average Stockholders’ Equity (annualized) ("ROAE") 10.10 10.05 (3) 12.80 13.20 (3) Adjusted PTPP ROAE (annualized) N/A 15.22 (3) N/A 18.28 (3) Book Value per Common Share(5) 32.25 N/A 30.90 N/A Tangible Book Value per Common Share(5) 26.53 31.03 (3) 25.09 30.29 (3) Return on Average Tangible Common Equity ("ROATCE") 12.34 12.29 (3) 16.00 16.50 (3) Efficiency Ratio 60.69 58.64 (3) 58.32 53.06 (3) ALCL to Total LHFI 1.25 1.30 (6) 1.23 1.28 (6) DOLLARS IN THOUSANDS, EXCEPT PER SHARE AMOUNTS, UNAUDITED 5 PERFORMANCE HIGHLIGHTS AT-A-GLANCE - FIRST QUARTER 2023 1Q23 Key Highlights * Please see slide 34 for all footnote references included above.

ORIGIN BANCORP, INC. _______ TRENDING KEY MEASURES 54,145 2Q 19 3Q 19 4Q 19 1Q 20 2Q 20 3Q 20 4Q 20 1Q 21 2Q 21 3Q 21 4Q 21 1Q 22 2Q 22 3Q 22 4Q 22 1Q 23 Total Revenue ($) UNAUDITED Diluted EPS ($)Net Income ($) Total LHFI, Adjusted ($)(7) Total Deposits ($) 0.52 0.79 2Q 19 3Q 19 4Q 19 1Q 20 2Q 20 3Q 20 4Q 20 1Q 21 2Q 21 3Q 21 4Q 21 1Q 22 2Q 22 3Q 22 4Q 22 1Q 23 2Q 19 3Q 19 4Q 19 1Q 20 2Q 20 3Q 20 4Q 20 1Q 21 2Q 21 3Q 21 4Q 21 1Q 22 2Q 22 3Q 22 4Q 22 1Q 23 3,855 8,174 2Q 19 3Q 19 4Q 19 1Q 20 2Q 20 3Q 20 4Q 20 1Q 21 2Q 21 3Q 21 4Q 21 1Q 22 2Q 22 3Q 22 4Q 22 1Q 23 3,760 7,038 2Q 19 3Q 19 4Q 19 1Q 20 2Q 20 3Q 20 4Q 20 1Q 21 2Q 21 3Q 21 4Q 21 1Q 22 2Q 22 3Q 22 4Q 22 1Q 23 DOLLARS IN THOUSANDS DOLLARS IN THOUSANDS 6 Total LHFI ($) DOLLARS IN MILLIONS 3,985 7,376 2Q 19 3Q 19 4Q 19 1Q 20 2Q 20 3Q 20 4Q 20 1Q 21 2Q 21 3Q 21 4Q 21 1Q 22 2Q 22 3Q 22 4Q 22 1Q 23 DOLLARS IN MILLIONS 24,302 12,283 93,531 DOLLARS IN MILLIONS * Please see slide 34 for all footnote references included above.

ORIGIN BANCORP, INC. _______ TRENDING KEY MEASURES CONTINUED Efficiency Ratio (%) 68.51 60.69 2Q 19 3Q 19 4Q 19 1Q 20 2Q 20 3Q 20 4Q 20 1Q 21 2Q 21 3Q 21 4Q 21 1Q 22 2Q 22 3Q 22 4Q 22 1Q 23 UNAUDITED Net Charge Offs ($) 677 1,311 2Q 19 3Q 19 4Q 19 1Q 20 2Q 20 3Q 20 4Q 20 1Q 21 2Q 21 3Q 21 4Q 21 1Q 22 2Q 22 3Q 22 4Q 22 1Q 23 Net Charge Offs to Total Average LHFI (%)(8) 0.07 0.07 2Q 19 3Q 19 4Q 19 1Q 20 2Q 20 3Q 20 4Q 20 1Q 21 2Q 21 3Q 21 4Q 21 1Q 22 2Q 22 3Q 22 4Q 22 1Q 23 Book Value per Common Share ($)(5) 0.98 1.01 2Q 19 3Q 19 4Q 19 1Q 20 2Q 20 3Q 20 4Q 20 1Q 21 2Q 21 3Q 21 4Q 21 1Q 22 2Q 22 3Q 22 4Q 22 1Q 23 ROAA (%)(8) 7 8.54 10.10 2Q 19 3Q 19 4Q 19 1Q 20 2Q 20 3Q 20 4Q 20 1Q 21 2Q 21 3Q 21 4Q 21 1Q 22 2Q 22 3Q 22 4Q 22 1Q 23 ROAE (%)(8) 24.58 32.25 2Q 19 3Q 19 4Q 19 1Q 20 2Q 20 3Q 20 4Q 20 1Q 21 2Q 21 3Q 21 4Q 21 1Q 22 2Q 22 3Q 22 4Q 22 1Q 23 * Please see slide 34 for all footnote references included above. DOLLARS IN THOUSANDS

ORIGIN BANCORP, INC. _______ TRENDING KEY NON-GAAP MEASURES(3) Adjusted Diluted EPS ($) UNAUDITED Adjusted Net Income ($) Adjusted PTPP Earnings ($) DOLLARS IN THOUSANDS Adjusted Efficiency Ratio (%) 65.38 58.64 2Q 19 3Q 19 4Q 19 1Q 20 2Q 20 3Q 20 4Q 20 1Q 21 2Q 21 3Q 21 4Q 21 1Q 22 2Q 22 3Q 22 4Q 22 1Q 23 23.22 26.53 2Q 19 3Q 19 4Q 19 1Q 20 2Q 20 3Q 20 4Q 20 1Q 21 2Q 21 3Q 21 4Q 21 1Q 22 2Q 22 3Q 22 4Q 22 1Q 23 Tangible Book Value per Common Share ($)(5) 8 22.99 31.03 2Q 19 3Q 19 4Q 19 1Q 20 2Q 20 3Q 20 4Q 20 1Q 21 2Q 21 3Q 21 4Q 21 1Q 22 2Q 22 3Q 22 4Q 22 1Q 23 Adjusted Tangible Book Value per Common Share ($) 2Q 19 3Q 19 4Q 19 1Q 20 2Q 20 3Q 20 4Q 20 1Q 21 2Q 21 3Q 21 4Q 21 1Q 22 2Q 22 3Q 22 4Q 22 1Q 23 DOLLARS IN THOUSANDS 2Q 19 3Q 19 4Q 19 1Q 20 2Q 20 3Q 20 4Q 20 1Q 21 2Q 21 3Q 21 4Q 21 1Q 22 2Q 22 3Q 22 4Q 22 1Q 23 0.50 2Q 19 3Q 19 4Q 19 1Q 20 2Q 20 3Q 20 4Q 20 1Q 21 2Q 21 3Q 21 4Q 21 1Q 22 2Q 22 3Q 22 4Q 22 1Q 23 0.78 16,683 11,993 24,188 36,627 * Please see slide 34 for all footnote references included above.

ORIGIN BANCORP, INC. _______ TRENDING KEY NON-GAAP MEASURES CONTINUED(3) Adjusted ROAE (%) UNAUDITED, ANNUALIZED Adjusted ROAA (%) Adjusted PTPP ROAA (%) Adjusted PTPP ROAE (%) 9.03 2Q 19 3Q 19 4Q 19 1Q 20 2Q 20 3Q 20 4Q 20 1Q 21 2Q 21 3Q 21 4Q 21 1Q 22 2Q 22 3Q 22 4Q 22 1Q 23 ROATCE (%)(9) 9 8.81 2Q 19 3Q 19 4Q 19 1Q 20 2Q 20 3Q 20 4Q 20 1Q 21 2Q 21 3Q 21 4Q 21 1Q 22 2Q 22 3Q 22 4Q 22 1Q 23 Adjusted ROATCE (%) 1.33 1.52 2Q 19 3Q 19 4Q 19 1Q 20 2Q 20 3Q 20 4Q 20 1Q 21 2Q 21 3Q 21 4Q 21 1Q 22 2Q 22 3Q 22 4Q 22 1Q 23 8.34 2Q 19 3Q 19 4Q 19 1Q 20 2Q 20 3Q 20 4Q 20 1Q 21 2Q 21 3Q 21 4Q 21 1Q 22 2Q 22 3Q 22 4Q 22 1Q 23 0.95 1.00 2Q 19 3Q 19 4Q 19 1Q 20 2Q 20 3Q 20 4Q 20 1Q 21 2Q 21 3Q 21 4Q 21 1Q 22 2Q 22 3Q 22 4Q 22 1Q 23 2Q 19 3Q 19 4Q 19 1Q 20 2Q 20 3Q 20 4Q 20 1Q 21 2Q 21 3Q 21 4Q 21 1Q 22 2Q 22 3Q 22 4Q 22 1Q 23 11.60 10.05 15.22 12.34 12.29 * Please see slide 34 for all footnote references included above.

ORIGIN BANCORP, INC. _______ ASSET AND STOCKHOLDERS' EQUITY GROWTH 1997 - 1Q23 UNAUDITED, DOLLARS IN MILLIONS Total Assets ($) 148 10,359 19 97 19 98 19 99 20 00 20 01 20 02 20 03 20 04 20 05 20 06 20 07 20 08 20 09 20 10 20 11 20 12 20 13 20 14 20 15 20 16 20 17 20 18 20 19 20 20 20 21 20 22 1Q 23 Total Stockholders' Equity ($) 11 993 19 97 19 98 19 99 20 00 20 01 20 02 20 03 20 04 20 05 20 06 20 07 20 08 20 09 20 10 20 11 20 12 20 13 20 14 20 15 20 16 20 17 20 18 20 19 20 20 20 21 20 22 1Q 23 CAGR 18.32% CAGR 19.52% 10 100 1,785 1,297 Origin Bancorp, Inc. Cumulative Return ($) KBW Nasdaq Bank Total Return Index ($) 12 /3 1/ 96 12 /3 1/ 97 12 /3 1/ 98 12 /3 1/ 99 12 /3 1/ 00 12 /3 1/ 01 12 /3 1/ 02 12 /3 1/ 03 12 /3 1/ 04 12 /3 1/ 05 12 /3 1/ 06 12 /3 1/ 07 12 /3 1/ 08 12 /3 1/ 09 12 /3 1/ 10 12 /3 1/ 11 12 /3 1/ 12 12 /3 1/ 13 12 /3 1/ 14 12 /3 1/ 15 12 /3 1/ 16 12 /3 1/ 17 12 /3 1/ 18 12 /3 1/ 19 12 /3 1/ 20 12 /3 1/ 21 12 /3 1/ 22 0 500 1,000 1,500 2,000 2,500 Total Shareholder Return ($)(10) IPO * Please see slide 34 for all footnote references included above. UNAUDITED, DOLLARS IN MILLIONS

ORIGIN BANCORP, INC. _______ 11 1,956 2,247 2,620 4,747 4,953 1,127 1,343 1,545 2,747 2,824829 904 1,075 1,631 1,754 369 375 DFW Houston East Texas 2019 2020 2021 2022 1Q23 Deposit Trends by Texas Market ($) Loan Trends by Texas Market ($)(12) TEXAS GROWTH STORY Texas Franchise Highlights DOLLARS IN MILLIONS, UNAUDITED • 35 locations throughout 10 counties including the 4th and 5th largest MSAs in the United States.(11) • Texas franchise represents 70% of LHFI, excluding mortgage warehouse loans, and 53% of deposits at March 31, 2023. 1,854 2,574 3,132 4,261 4,196 989 1,581 1,925 2,196 2,053 865 993 1,207 1,173 1,261 892 882 DFW Houston East Texas 2019 2020 2021 2022 1Q23 CAGR 33.1% CAGR 28.6% * Please see slide 34 for all footnote references included above. DOLLARS IN MILLIONS, UNAUDITED

ORIGIN BANCORP, INC. _______ 12 LOAN GROWTH 3,869 4,094 4,498 7,038 6,805 5,593 1,212 Origin BTH 2019 2020 2021 2022 1Q23 2,000 4,000 6,000 8,000 LHFI Key Data DOLLARS IN MILLIONS, UNAUDITED IDT • Total loans held for investment ("LHFI"), excluding mortgage warehouse lines of credit, were $7.04 billion at March 31, 2023, reflecting an increase of $233.1 million, or 3.4%, compared to December 31, 2022. • Total mortgage warehouse lines of credit were $337.5 million, or 4.6%, of total LHFI at March 31, 2023. LHFI Growth excluding MW LOC ($)(13) CAGR: 20.2% 1,902 1,833 2,032 3,2003,160 2,492 668 Origin BTH 2019 2020 2021 2022 1Q23 1,000 2,000 3,000 4,000 C&I, Owner Occupied CRE and C&D Growth ($)(13) CAGR: 17.4% * Please see slide 34 for all footnote references included above. DOLLARS IN MILLIONS, UNAUDITED

ORIGIN BANCORP, INC. _______ Real Estate & Construction: 8% Retail Shopping: 7% Office Building: 5% Healthcare: 3% Multi-family under construction: 2% Hotel: 1% Restaurant: 1% Finance & Insurance: 1% Professional Svcs.: 1% Misc.: 1% Commercial & Industrial ("C&I") 28% Owner Occupied Construction/ Land/Land Development ("C&D"): 3% Owner Occupied Commercial Real Estate ("CRE"):12% Mtg. WH LOC: 5% Non- Owner Occupied C&D: 9% Non-Owner Occupied CRE: 21% Residential Real Estate & Consumer 22% Real Estate & Construction: 9% Finance & Insurance: 6% Mtg. WH LOC: 5% Transportation Svcs: 3% Energy: 3% Retail Dealers: 2% Healthcare: 2% Commercial Svcs: 2% Retail Shopping: 2% Restaurants: 2% Consumer Svcs: 1% Banks: 1% Professional Svcs: 1% Materials&Commodities: 1% Entertainment: 1% Misc: 7% 13 WELL DIVERSIFIED LOAN PORTFOLIO(14) (Dollars in thousands) 1Q23 4Q22 3Q22 2Q22 1Q22 C&I (15) $ 2,091,093 $ 2,051,161 $ 1,967,037 $ 1,429,338 $ 1,326,443 Owner Occupied CRE 855,887 843,006 800,981 609,358 588,279 Owner Occupied C&D 252,617 265,838 248,602 187,249 179,074 Mtg. WH LOC 337,529 284,867 460,573 531,888 503,249 Total Commercial 3,537,126 3,444,872 3,477,193 2,757,833 2,597,045 Non-Owner Occupied CRE 1,529,513 1,461,672 1,373,366 1,299,696 1,213,103 Non-Owner Occupied C&D 696,009 679,787 604,709 448,307 414,276 Residential Real Estate- Single Family Real Estate 1,231,022 1,173,316 1,104,277 726,410 700,457 Residential Real Estate- Multi-Family Real Estate 357,469 304,222 294,905 279,213 221,597 Consumer Loans 24,684 26,153 28,231 15,733 15,774 PPP Loans (15) — — — 901 32,154 Total Loans $ 7,375,823 $ 7,090,022 $ 6,882,681 $ 5,528,093 $ 5,194,406 Loan Portfolio Details Non-Owner Occupied CRE and C&D: $2,226 million C&I, Owner Occupied CRE and C&D, MW LOC: $3,537 million C&I, Owner Occupied CRE and C&D, Mtg. WH LOC: 48% Non-Owner Occupied CRE and C&D: 30% Loan Composition at March 31, 2023: $7,376 million * Please see slide 34 for all footnote references included above.

ORIGIN BANCORP, INC. _______ 1.01 1.05 1.17 Classified LHFI / Total LHFI, adjusted (%) Net Charge-Offs / Average LHFI (annualized) (%) 1Q22 2Q22 3Q22 4Q22 1Q23 0.07 0.01 0.07 0.20 0.14 0.230.16 0.15 0.16 Nonperforming LHFI / LHFI (%) Past due LHFI / LHFI (%) 1Q22 2Q22 3Q22 4Q22 1Q23 14 CREDIT QUALITY Asset Quality Trends (%) Allowance for Loan Credit Losses ("ALCL") 62,173 63,123 83,359 87,161 92,008 1.20 1.14 1.21 1.23 1.25 1.33 1.25 1.29 1.28 1.30 ALCL as a percentage of LHFI, adjusted (%) ALCL as a percentage of LHFI (%) ALCL ($) 1Q22 2Q22 3Q22 4Q22 1Q23 • Provision for credit loss expense for 1Q23 was $6.2 million, compared to a provision credit loss expense of $4.6 million in 4Q22, and compared to a provision net benefit of $327,000 in 1Q22. • ALCL to nonperforming LHFI is 538.75% at 1Q23, 876.87% at 3Q22, and 293.53% at 1Q22. DOLLARS IN THOUSANDS, UNAUDITED 0.14(16) 0.41(16) 0.42(16) 0.25(16) 0.13(16) (6) 0.12(16) 1.36(16) 0.94(16) * Please see slide 34 for all footnote references included above.

ORIGIN BANCORP, INC. _______ Texas: 73% Louisiana: 8% Mississippi: 14% Out of Market: 5% 15 Medical: 24% Financial: 15% Law Firms: 10%Energy: 10% Other: 22% National Credit Tenant: 19% CRE OFFICE - STRENGTH AND DIVERSIFICATION Tenant Classification $380.5M $380.5M Geographic Diversification DOLLARS IN THOUSANDS, UNAUDITED 03/31/2023 Avg. Loan Size $ 2,199 Weighted Avg. LTV 53.30 % Past Due Loans / Loans — Classified Loans / Loans 0.22 NPL / Loans — NCOs / Avg. Loans (annualized) — ALCL / Loans 0.85 * Please see slide 34 for all footnote references included above. Key Portfolio Metrics DOLLARS IN MILLIONS, UNAUDITED DOLLARS IN MILLIONS, UNAUDITED

ORIGIN BANCORP, INC. _______ Treasury/Agency: 15% MBS: 41% CMO: 12% Municipal: 23% Corporate/ABS: 9% 1,662 1,869 1,865 1,675 1,634 1.59 1.85 2.12 2.34 2.38 Total Securities ($) Yield (%) 1Q22 2Q22 3Q22 4Q22 1Q23 Investment Securities Average Balance and Yield INVESTMENT SECURITIES DOLLARS IN MILLIONS, UNAUDITED • The fair value of the held to maturity securities portfolio totaled $12.0 million at 1Q23, compared to $12.0 million at 4Q22. • Securities of $38.7 million were sold during the current quarter, and realized a net gain of $144,000. • Total securities portfolio weighted average effective duration was 4.17 years as of March 31, 2023, compared to 4.24 years as of December 31, 2022. 16 (65.9) (116.0) (175.2) (159.9) (138.5) 1Q22 2Q22 3Q22 4Q22 1Q23 Accumulated Other Comprehensive (Loss) Income(17) ($) Investment Securities - AFS * Please see slide 34 for all footnote references included above. $1.6B DOLLARS IN MILLIONS, UNAUDITED

ORIGIN BANCORP, INC. _______ Commercial: 52% Consumer: 33% Public: 11% Brokered: 4% Real Estate Rental & Leasing: 7% Finance & Insurance: 6% Professional, Scientific, & Technical Svcs: 6% Construction: 6% Mgmt of Companies & Enterprises: 4% Affiliate: 3% Other Business Deposits 1% or less: 3% Manufacturing: 2% Healthcare & Social Assistance: 2% Mining: 2% Other Svcs (except Public Admin.): 2% Retail Trade: 1% Misc: 6% 17 DEPOSIT DETAIL (Dollars in thousands) 1Q23 4Q22 QoQ % Δ Total Deposits $ 8,174,310 $ 7,775,702 5.1 % FDIC Insured (3,425,845) (3,331,724) 2.8 FDIC Insured Reciprocal (531,051) (245,621) 116.2 FDIC Insured Brokered time deposits & CDARS (289,968) (5,407) not meaningful Total Estimated FDIC Uninsured Deposits 3,927,446 4,192,950 (6.3) Collateralized Public Funds (839,569) (762,366) 10.1 Uninsured/Uncollateralized Deposits ($) $ 3,087,877 $ 3,430,584 (10.0) Uninsured/Uncollateralized Deposits (%) 37.8 % 44.1 % Deposit Detail Geographic Concentration Commercial Deposit Composition: $4,253 millionDeposit Composition at March 31, 2023: $8,174 million Commercial Public Funds 33% 17% 6% 38% 6% Consumer MississippiLouisiana Texas- DFW TX- East TexasTexas- Houston Agriculture, Forestry, Fishing & Hunting: 1% * Please see slide 34 for all footnote references included above. Wholesale Trade: 1% 18% 17% 19% 37% 9% 7% 2% 14% 57% 20%

ORIGIN BANCORP, INC. _______ 18 6,729 6,559 7,410 7,710 8,017 3,976 3,767 4,157 4,363 4,648 2,218 2,289 2,583 2,593 2,392 535 503 670 754 977 Interest-bearing Demand Noninterest-bearing Time Deposits 1Q22 2Q22 3Q22 4Q22 1Q23 Average Deposits ($) DEPOSIT TRENDS 0.54 0.49 2.58 0.64 1.54 2.49 0.41 1.02 1.75 Time Deposits Cost of Interest-bearing Deposits Cost of Total Deposits 1Q22 2Q22 3Q22 4Q22 1Q23 Deposit Cost Trends (QTD Annualized) (%) IDT Total Deposit Beta (%) 0.19 0.510.290.26 Full Cycle Total Deposit Betas (%) 44.0 27.029.0 30.0 Peer OBNK 2Q2004 - 3Q2006 4Q2015 - 1Q2019 (18) 0.17 1.22 -50 * Please see slide 34 for all footnote references included above. DOLLARS IN MILLIONS, UNAUDITED 0.0 10.0 23.0 36.0 0.12 0.77 2.18 3.65 4.51 Cumulative Deposit Beta Average Quarterly Fed Funds Rate 1Q22 2Q22 3Q22 4Q22 1Q23

ORIGIN BANCORP, INC. _______ 19 YIELDS AND COSTS Yield on LHFI (%) 4.08 4.26 6.03 4.86 5.94 3.29 5.36 6.82 7.69 0.23 1.02 2.47 3.91 4.62 2.14 3.62 4.49 Yield on LHFI Yield on LHFI excl. PPP Loans and PAA Avg. Prime Rate Avg. 1M LIBOR Avg. SOFR 1Q22 2Q22 3Q22 4Q22 1Q23 Cost of Funds (%) 0.33 0.35 2.01 1.54 2.49 1.02 1.75 Cost of Total Deposits & Borrowings Cost of Interest Bearing Deposits Cost of Total Deposits Cost of Total Deposits & Borrowings excl. PAA 1Q22 2Q22 3Q22 4Q22 1Q23 0.26 0.17 0.19 0.29 • LHFI with fixed rate: 44%; LHFI with floating rate: 56% at 1Q23. • $996.5 million LIBOR-based(20), $2.13 billion Prime-based and $993.0 million primarily SOFR-based loans at 1Q23. 3.95 4.21 (19) 0.64 0.09 3.94 5.53 5.63 0.62 0.63 4.94 0.71 0.41 1.26 1.24 * Please see slide 34 for all footnote references included above.

ORIGIN BANCORP, INC. _______ 20 DOLLARS IN THOUSANDS, UNAUDITED 52,502 59,504 78,523 84,749 77,147 46,202 54,241 71,494 78,174 72,435 3,897 4,544 5,614 4,678 3,009 2,403 719 1,415 1,897 1,703 2.86 3.23 3.68 3.81 3.44 2.76 3.20 3.61 3.73 3.36 Net Interest Income excl. MW LOC, adjusted ($) MW LOC Interest Income ($) PPP Interest Income ($) Net Purchase Accounting Accretion ($) NIM (FTE) (%) NIM (FTE), adjusted (%) 1Q22 2Q22 3Q22 4Q22 1Q23 NET INTEREST INCOME AND NIM TRENDS 3.44 3.81 0.21 0.16 0.02 0.01 (0.02) (0.03) (0.10) (0.14) (0.48) 4Q 22 RE Lo an s C&I L oa ns IB B al. D FB Inv es tm en t S ec . Othe r Mtg. W H LO C FH LB & O the r Bor ro wing s Tim e D ep os its Sav ing s a nd IB Tr an sc . A cc ts 1Q 23 2.50 3.00 3.50 4.00 4.50 Net Interest Income Changes - 1Q23 (%) Full Cycle NIM Betas (%) (21) (21) (2.0) 13.015.0 21.0 Peer OBNK 2Q2004 - 3Q2006 4Q2015 - 1Q2019 (18) * Please see slide 34 for all footnote references included above.

ORIGIN BANCORP, INC. _______ Insurance Commission & Fee Income Service Charges & Fees Mortgage Banking Revenue Other 2Q19 3Q19 4Q19 1Q20 2Q20 3Q20 4Q20 1Q21 2Q21 3Q21 4Q21 1Q22 2Q22 3Q22 4Q22 1Q23 21 Net Interest Income Noninterest Income 2Q19 3Q19 4Q19 1Q20 2Q20 3Q20 4Q20 1Q21 2Q21 3Q21 4Q21 1Q22 2Q22 3Q22 4Q22 1Q23 Noninterest Income ($)(22) Net Interest Income + Noninterest Income ($) NET REVENUE DISTRIBUTION Components of Other Noninterest Income 93,531 1Q23 4Q22 3Q22 2Q22 1Q22 Limited Partnership Investment Income $ 66 $ (230) $ 112 $ 282 $ (363) Swap Fee Income 384 292 25 1 139 Gain on Sale of Securities 144 — 1,664 — — GNMA MSR impairment(22) — — (1,950) — — Other 2,427 2,449 2,452 1,612 1,580 Total $ 3,021 $ 2,511 $ 2,303 $ 1,895 $ 1,356 54,145 16,384 79.4% 82.5% 11,176 * Please see slide 34 for all footnote references included above. DOLLARS IN THOUSANDS, UNAUDITED

ORIGIN BANCORP, INC. _______ 42,774 44,150 56,241 57,254 56,760 26,488 27,310 31,834 33,339 33,731 4,427 4,514 5,399 5,863 6,503 2,486 2,413 2,689 2,868 2,9161,872 2,554 2,553 1,560 2,162 2,121 2,277 2,303 1,305 1,517 1,599 1,6763,614 5,400 4,902 7,113 7,498 7,289 Salaries and Employee Benefits Occupancy and Equipment, net Data Processing Intangible Asset Amortization Office and Operations Loan-related Expenses Merger Transaction Expense Other 1Q22 2Q22 3Q22 4Q22 1Q23 22 Efficiency Ratios (%)(3) NONINTEREST EXPENSE ANALYSIS DOLLARS IN THOUSANDS, UNAUDITED Noninterest Expense Composition ($) Consolidated Efficiency Ratio Adjusted Efficiency Ratio 1Q22 2Q22 3Q22 4Q22 1Q23 62 .5 3 59 .8 9 58 .9 3 54 .1 0 Operating Leverage (%) E FF IC IE N C Y R A TI O (% ) N IE / A V E R A G E A S S E TS (% ) 2.17 2.03 2.08 2.12 2.16 2.23 2.42 2.38 2.35 54.49 56.69 57.21 56.92 62.53 59.89 60.97 58.32 60.69 1Q21 2Q21 3Q21 4Q21 1Q22 2Q22 3Q22 4Q22 1Q23 40 60 80 100 1.5 2.0 2.5 3.0 60 .9 7 52 .1 6 58 .3 2 53 .0 6 58 .6 4 60 .6 9 571 807 1,179 1,465 537 525 * Please see slide 34 for all footnote references included above.

ORIGIN BANCORP, INC. _______ 8.8 9.1 9.6 9.7 9.89.3 9.5 9.1 9.9 10.2 Company Level Origin Bank Level 1Q22 2Q22 3Q22 4Q22 1Q23 11.3 11.0 10.7 11.1 11.3 11.9 11.4 10.9 11.5 11.7 Company Level Origin Bank Level 1Q22 2Q22 3Q22 4Q22 1Q23 23 CAPITAL Bank Level Company Level Sub-debt Impact 14.6 14.1 13.8 14.2 14.3 13.9 13.4 12.8 13.4 13.6 Company Level Origin Bank Level 1Q22 2Q22 3Q22 4Q22 1Q23 Tangible Common Equity To Tangible Assets(3) ICap ICap Total Capital to Risk-Weighted Assets (%)(23)Tier 1 Capital to Risk-Weighted Assets (%)(23) Tier 1 Capital to Average Assets (Leverage Ratio) (%)(23)(24) * Please see slide 34 for all footnote references included above. 8,062 8,061 9,273 9,508 10,183 626 596 718 771 817 Tangible Assets ($) Tangible Equity ($) 1Q22 2Q22 3Q22 4Q22 1Q23 7.8 7.4 7.7 8.1 8.0 Company Level DOLLARS IN THOUSANDS, UNAUDITED

ORIGIN BANCORP, INC. _______ Calculation of adjusted net income: 1Q23 4Q22 3Q22 2Q22 1Q22 4Q21 3Q21 2Q21 Net interest income after provision for credit losses $ 70,950 $ 80,125 $ 61,581 $ 56,052 $ 52,829 $ 56,827 $ 56,462 $ 59,901 Add: CECL provision for non-PCD loans — — 14,890 — — — — — Adjusted net interest income after provision for credit losses 70,950 80,125 76,471 56,052 52,829 56,827 56,462 59,901 Total noninterest income $ 16,384 $ 13,429 $ 13,723 $ 14,216 $ 15,906 $ 16,701 $ 15,923 $ 12,438 Less: GNMA MSR impairment — — (1,950) — — — — — Less: Gain on sales of securities, net 144 — 1,664 — — 75 — 5 Less: Gain on fair value of the Lincoln Agency — — — — — 5,213 — — Adjusted total noninterest income 16,240 13,429 14,009 14,216 15,906 11,413 15,923 12,433 Total noninterest expense $ 56,760 $ 57,254 $ 56,241 $ 44,150 $ 42,774 $ 40,346 $ 39,165 $ 37,832 Less: Merger expense — 1,179 3,614 807 571 — — — Adjusted total noninterest expense 56,760 56,075 52,627 43,343 42,203 40,346 39,165 37,832 Income tax expense $ 6,272 $ 6,822 $ 2,820 $ 4,807 $ 5,278 $ 4,860 $ 6,242 $ 6,774 Add: Income tax expense on adjustment items (30) 248 3,946 169 120 (1,110) — (1) Adjusted income tax expense 6,242 7,070 6,766 4,976 5,398 3,750 6,242 6,773 Net income $ 24,302 $ 29,478 $ 16,243 $ 21,311 $ 20,683 $ 28,322 $ 26,978 $ 27,733 Adjusted net income $ 24,188 $ 30,409 $ 31,087 $ 21,949 $ 21,134 $ 24,144 $ 26,978 $ 27,729 24 DOLLARS IN THOUSANDS, UNAUDITED RECONCILIATION OF NON-GAAP FINANCIAL MEASURES

ORIGIN BANCORP, INC. _______ Calculation of adjusted net income, continued: 1Q21 4Q20 3Q20 2Q20 1Q20 4Q19 3Q19 2Q19 Net interest income after provision for credit losses $ 53,827 $ 45,486 $ 36,984 $ 24,887 $ 24,279 $ 41,718 $ 40,421 $ 40,984 Total noninterest income $ 17,131 $ 15,381 $ 18,051 $ 19,076 $ 12,144 $ 10,818 $ 12,880 $ 11,176 Less: Valuation adjustment on non-marketable equity security — — — — — — — 367 Less: Gain on sales of securities, net 1,668 225 301 — 54 — 20 — Less: Bank-owned life insurance policy — — — — 316 — — — Adjusted total noninterest income 15,463 15,156 17,750 19,076 11,774 10,818 12,860 10,809 Total noninterest expense $ 39,436 $ 38,884 $ 38,734 $ 38,220 $ 36,097 $ 36,534 $ 35,064 $ 37,095 Less: FDIC fund assessment benefit — — — — — — (1,037) — Less: Early termination of LT FHLB advance 1,613 — — — — — — — Adjusted total noninterest expense 37,823 38,884 38,734 38,220 36,097 36,534 36,101 37,095 Income tax expense $ 6,009 $ 4,431 $ 3,206 $ 786 $ (427) $ 3,175 $ 3,620 $ 2,782 Add: Income tax expense on adjustment items (12) (47) (63) — (78) — (222) (77) Adjusted income tax expense 5,997 4,384 3,143 786 (505) 3,175 3,398 2,705 Net income $ 25,513 $ 17,552 $ 13,095 $ 4,957 $ 753 $ 12,827 $ 14,617 $ 12,283 Adjusted net income $ 25,470 $ 17,374 $ 12,857 $ 4,957 $ 461 $ 12,827 $ 13,782 $ 11,993 25 DOLLARS IN THOUSANDS, UNAUDITED RECONCILIATION OF NON-GAAP FINANCIAL MEASURES

ORIGIN BANCORP, INC. _______ Calculation of adjusted PTPP earnings: 1Q23 4Q22 3Q22 2Q22 1Q22 4Q21 3Q21 2Q21 Provision for credit losses $ 6,197 $ 4,624 $ 16,942 $ 3,452 $ (327) $ (2,647) $ (3,921) $ (5,609) Less: CECL provision for non-PCD loans — — 14,890 — — — — — Adjusted provision for credit losses $ 6,197 $ 4,624 $ 2,052 $ 3,452 $ (327) $ (2,647) $ (3,921) $ (5,609) Adjusted net income $ 24,188 $ 30,409 $ 31,087 $ 21,949 $ 21,134 $ 24,144 $ 26,978 $ 27,729 Plus: Adjusted provision for credit losses 6,197 4,624 2,052 3,452 (327) (2,647) (3,921) (5,609) Plus: Adjusted income tax expense 6,242 7,070 6,766 4,976 5,398 3,750 6,242 6,773 Adjusted PTPP earnings $ 36,627 $ 42,103 $ 39,905 $ 30,377 $ 26,205 $ 25,247 $ 29,299 $ 28,893 1Q21 4Q20 3Q20 2Q20 1Q20 4Q19 3Q19 2Q19 Provision for credit losses $ 1,412 $ 6,333 $ 13,633 $ 21,403 $ 18,531 $ 2,377 $ 4,201 $ 1,985 Less: CECL provision for non-PCD loans — — — — — — — — Adjusted provision for credit losses $ 1,412 $ 6,333 $ 13,633 $ 21,403 $ 18,531 $ 2,377 $ 4,201 $ 1,985 Adjusted net income $ 25,470 $ 17,374 $ 12,857 $ 4,957 $ 461 $ 12,827 $ 13,782 $ 11,993 Plus: Adjusted provision for credit losses 1,412 6,333 13,633 21,403 18,531 2,377 4,201 1,985 Plus: Adjusted income tax expense 5,997 4,384 3,143 786 (505) 3,175 3,398 2,705 Adjusted PTPP earnings $ 32,879 $ 28,091 $ 29,633 $ 27,146 $ 18,487 $ 18,379 $ 21,381 $ 16,683 26 DOLLARS IN THOUSANDS, UNAUDITED RECONCILIATION OF NON-GAAP FINANCIAL MEASURES

ORIGIN BANCORP, INC. _______ Calculation of adjusted dilutive EPS: 1Q23 4Q22 3Q22 2Q22 1Q22 4Q21 3Q21 2Q21 Numerator: Adjusted net income $ 24,188 $ 30,409 $ 31,087 $ 21,949 $ 21,134 $ 24,144 $ 26,978 $ 27,729 Denominator: Weighted average diluted common shares outstanding 30,882,156 30,867,511 28,481,619 23,788,164 23,770,791 23,609,874 23,613,010 23,604,566 Diluted earnings per share $ 0.79 $ 0.95 $ 0.57 $ 0.90 $ 0.87 $ 1.20 $ 1.14 $ 1.17 Adjusted diluted earnings per share 0.78 0.99 1.09 0.92 0.89 1.02 1.14 1.17 1Q21 4Q20 3Q20 2Q20 1Q20 4Q19 3Q19 2Q19 Numerator: Adjusted net income $ 25,470 $ 17,374 $ 12,857 $ 4,957 $ 461 $ 12,827 $ 13,782 $ 11,993 Denominator: Weighted average diluted common shares outstanding 23,590,430 23,543,917 23,500,596 23,466,326 23,530,212 23,529,862 23,606,956 23,786,646 Diluted earnings per share $ 1.08 $ 0.75 $ 0.56 $ 0.21 $ 0.03 $ 0.55 $ 0.62 $ 0.52 Adjusted diluted earnings per share 1.08 0.74 0.55 0.21 0.02 0.55 0.58 0.50 27 RECONCILIATION OF NON-GAAP FINANCIAL MEASURES DOLLARS IN THOUSANDS, EXCEPT PER SHARE AMOUNTS, UNAUDITED

ORIGIN BANCORP, INC. _______ Calculation of adjusted ROAA and ROAE: 1Q23 4Q22 3Q22 2Q22 1Q22 4Q21 3Q21 2Q21 Adjusted net income $ 24,188 $ 30,409 $ 31,087 $ 21,949 $ 21,134 $ 24,144 $ 26,978 $ 27,729 Divided by number of days in the quarter 90 92 92 91 90 92 92 91 Multiplied by the number of days in the year 365 365 365 365 365 365 365 365 Annualized adjusted net income $ 98,096 $ 120,644 $ 123,334 $ 88,037 $ 85,710 $ 95,789 $ 107,032 $ 111,221 Divided by total average assets 9,783,602 9,530,543 9,202,421 7,944,720 8,045,246 7,559,570 7,464,813 7,474,951 ROAA (annualized) 1.01 % 1.23 % 0.70 % 1.08 % 1.04 % 1.49 % 1.43 % 1.49 % Adjusted ROAA (annualized) 1.00 1.27 1.34 1.11 1.07 1.27 1.43 1.49 Divided by total average stockholders' equity $ 976,044 $ 913,850 $ 938,752 $ 667,323 $ 722,504 $ 715,614 $ 703,605 $ 672,698 ROAE (annualized) 10.10 % 12.80 % 6.86 % 12.81 % 11.61 % 15.70 % 15.21 % 16.54 % Adjusted ROAE (annualized) 10.05 13.20 13.14 13.19 11.86 13.39 15.21 16.53 1Q21 4Q20 3Q20 2Q20 1Q20 4Q19 3Q19 2Q19 Adjusted net income $ 25,470 $ 17,374 $ 12,857 $ 4,957 $ 461 $ 12,827 $ 13,782 $ 11,993 Divided by number of days in the quarter 90 92 92 91 91 92 92 91 Multiplied by the number of days in the year 365 366 366 366 366 365 365 365 Annualized adjusted net income $ 103,295 $ 69,118 $ 51,149 $ 19,937 $ 1,854 $ 50,890 $ 54,679 $ 48,104 Divided by total average assets 7,382,495 7,164,028 6,746,585 6,447,526 5,400,704 5,271,979 5,179,549 5,043,951 ROAA (annualized) 1.40 % 0.97 % 0.77 % 0.31 % 0.06 % 0.97 % 1.12 % 0.98 % Adjusted ROAA (annualized) 1.40 0.96 0.76 0.31 0.03 0.97 1.06 0.95 Divided by total average stockholders' equity $ 657,863 $ 639,508 $ 629,533 $ 617,898 $ 611,162 $ 597,925 $ 588,504 $ 576,761 ROAE (annualized) 15.73 % 10.92 % 8.28 % 3.23 % 0.50 % 8.51 % 9.85 % 8.54 % Adjusted ROAE (annualized) 15.70 10.81 8.12 3.23 0.30 8.51 9.29 8.34 28 DOLLARS IN THOUSANDS, UNAUDITED RECONCILIATION OF NON-GAAP FINANCIAL MEASURES

ORIGIN BANCORP, INC. _______ Calculation of adjusted PTPP ROAA & ROAE: 1Q23 4Q22 3Q22 2Q22 1Q22 4Q21 3Q21 2Q21 Adjusted PTPP earnings $ 36,627 $ 42,103 $ 39,905 $ 30,377 $ 26,205 $ 25,247 $ 29,299 $ 28,893 Divided by number of days in the quarter 90 92 92 91 90 92 92 91 Multiplied by the number of days in the year 365 365 365 365 365 365 365 365 Adjusted PTPP earnings, annualized $ 148,543 $ 167,039 $ 158,319 $ 121,842 $ 106,276 $ 100,165 $ 116,241 $ 115,890 Divided by total average assets 9,783,602 9,530,543 9,202,421 7,944,720 8,045,246 7,559,570 7,464,813 7,474,951 Adjusted PTPP ROAA (annualized) 1.52 % 1.75 % 1.72 % 1.53 % 1.32 % 1.33 % 1.56 % 1.55 % Divided by total average stockholders' equity $ 976,044 $ 913,850 $ 938,752 $ 667,323 $ 722,504 $ 715,614 $ 703,605 $ 672,698 Adjusted PTPP ROAE (annualized) 15.22 % 18.28 % 16.86 % 18.26 % 14.71 % 14.00 % 16.52 % 17.23 % 1Q21 4Q20 3Q20 2Q20 1Q20 4Q19 3Q19 2Q19 Adjusted PTPP earnings $ 32,879 $ 28,091 $ 29,633 $ 27,146 $ 18,487 $ 18,379 $ 21,381 $ 16,683 Divided by number of days in the quarter 90 92 92 91 91 92 92 91 Multiplied by the number of days in the year 365 366 366 366 366 365 365 365 Adjusted PTPP earnings, annualized $ 133,343 $ 111,753 $ 117,888 $ 109,181 $ 74,354 $ 72,917 $ 84,827 $ 66,915 Divided by total average assets 7,382,495 7,164,028 6,746,585 6,447,526 5,400,704 5,271,979 5,179,549 5,043,951 Adjusted PTPP ROAA (annualized) 1.81 % 1.56 % 1.75 % 1.69 % 1.38 % 1.38 % 1.64 % 1.33 % Divided by total average stockholders' equity $ 657,863 $ 639,508 $ 629,533 $ 617,898 $ 611,162 $ 597,925 $ 588,504 $ 576,761 Adjusted PTPP ROAE (annualized) 20.27 % 17.47 % 18.73 % 17.67 % 12.17 % 12.20 % 14.41 % 11.60 % 29 DOLLARS IN THOUSANDS, UNAUDITED RECONCILIATION OF NON-GAAP FINANCIAL MEASURES

ORIGIN BANCORP, INC. _______ Calculation of tangible book value per common share, adjusted tangible book value per common share and tangible common equity to total assets: 1Q23 4Q22 3Q22 2Q22 1Q22 4Q21 3Q21 2Q21 Total assets $ 10,358,516 $ 9,686,067 $ 9,462,639 $ 8,111,524 $ 8,112,295 $ 7,861,285 $ 7,470,478 $ 7,268,068 Less: Goodwill 128,679 128,679 136,793 34,153 34,153 34,368 26,741 26,741 Less: Other intangible assets, net 47,277 49,829 52,384 15,900 16,425 16,962 3,089 3,283 Tangible assets 10,182,560 9,507,559 9,273,462 8,061,471 8,061,717 7,809,955 7,440,648 7,238,044 Total common stockholders' equity $ 992,587 $ 949,943 $ 907,024 $ 646,373 $ 676,865 $ 730,211 $ 705,667 $ 688,235 Less: Goodwill 128,679 128,679 136,793 34,153 34,153 34,368 26,741 26,741 Less: Other intangible assets, net 47,277 49,829 52,384 15,900 16,425 16,962 3,089 3,283 Tangible common equity 816,631 771,435 717,847 596,320 626,287 678,881 675,837 658,211 Less: Accumulated other comprehensive (loss) income (138,481) (159,875) (175,233) (115,979) (65,890) 5,729 11,872 18,914 Adjusted tangible common equity 955,112 931,310 893,080 712,299 692,177 673,152 663,965 639,297 Divided by common shares outstanding at period end 30,780,853 30,746,600 30,661,734 23,807,677 23,748,748 23,746,502 23,496,058 23,502,215 Book value per common share(5) $ 32.25 $ 30.90 $ 29.58 $ 27.15 $ 28.50 $ 30.75 $ 30.03 $ 29.28 Tangible book value per common share(5) 26.53 25.09 23.41 25.05 26.37 28.59 28.76 28.01 Adjusted tangible book value per common share 31.03 30.29 29.13 29.92 29.15 28.35 28.26 27.20 Tangible common equity to tangible assets 8.02 % 8.11 % 7.74 % 7.40 % 7.77 % 8.69 % 9.08 % 9.09 % 30 RECONCILIATION OF NON-GAAP FINANCIAL MEASURES * Please see slide 34 for all footnote references included above. DOLLARS IN THOUSANDS, EXCEPT PER SHARE AMOUNTS, UNAUDITED

ORIGIN BANCORP, INC. _______ Calculation of tangible book value per common share, adjusted tangible book value per common share and tangible common equity to total assets, continued: 1Q21 4Q20 3Q20 2Q20 1Q20 4Q19 3Q19 2Q19 Total assets $ 7,563,175 $ 7,628,268 $ 7,101,338 $ 6,643,909 $ 6,049,638 $ 5,324,626 $ 5,396,928 $ 5,119,625 Less: Goodwill 26,741 26,741 26,741 26,741 26,741 26,741 26,741 26,741 Less: Other intangible assets, net 3,505 3,739 3,976 4,212 4,500 4,799 5,101 5,403 Tangible assets 7,532,929 7,597,788 7,070,621 6,612,956 6,018,397 5,293,086 5,365,086 5,087,481 Total common stockholders' equity $ 656,355 $ 647,150 $ 627,637 $ 614,781 $ 606,631 $ 599,362 $ 588,363 $ 584,293 Less: Goodwill 26,741 26,741 26,741 26,741 26,741 26,741 26,741 26,741 Less: Other intangible assets, net 3,505 3,739 3,976 4,212 4,500 4,799 5,101 5,403 Tangible common equity 626,109 616,670 596,920 583,828 575,390 567,822 556,521 552,149 Less: Accumulated other comprehensive (loss) income 12,185 25,649 21,998 20,613 15,822 6,333 6,690 5,619 Adjusted tangible common equity 613,924 591,021 574,922 563,215 559,568 561,489 549,831 546,530 Divided by common shares outstanding at period end 23,488,884 23,506,312 23,506,586 23,501,233 23,475,948 23,480,945 23,481,781 23,774,238 Book value per common share(5) $ 27.94 $ 27.53 $ 26.70 $ 26.16 $ 25.84 $ 25.52 $ 25.06 $ 24.58 Tangible book value per common share(5) 26.66 26.23 25.39 24.84 24.51 24.18 23.70 23.22 Adjusted tangible book value per common share 26.14 25.14 24.46 23.97 23.84 23.91 23.42 22.99 Tangible common equity to tangible assets 8.31 % 8.12 % 8.44 % 8.83 % 9.56 % 10.73 % 10.37 % 10.85 % 31 RECONCILIATION OF NON-GAAP FINANCIAL MEASURES * Please see slide 34 for all footnote references included above. DOLLARS IN THOUSANDS, EXCEPT PER SHARE AMOUNTS, UNAUDITED

ORIGIN BANCORP, INC. _______ Calculation of ROATCE and Adjusted ROATCE: 1Q23 4Q22 3Q22 2Q22 1Q22 4Q21 3Q21 2Q21 Net income $ 24,302 $ 29,478 $ 16,243 $ 21,311 $ 20,683 $ 28,322 $ 26,978 $ 27,733 Divided by number of days in the quarter 90 92 92 91 90 92 92 91 Multiplied by number of days in the year 365 365 365 365 365 365 365 365 Annualized net income $ 98,558 $ 116,951 $ 64,442 $ 85,478 $ 83,881 $ 112,364 $ 107,032 $ 111,237 Adjusted net income $ 24,188 $ 30,409 $ 31,087 $ 21,949 $ 21,134 $ 24,144 $ 26,978 $ 27,729 Divided by number of days in the quarter 90 92 92 91 90 92 92 91 Multiplied by number of days in the year 365 365 365 365 365 365 365 365 Annualized adjusted net income $ 98,096 $ 120,644 $ 123,334 $ 88,037 $ 85,710 $ 95,789 $ 107,032 $ 111,221 Total average common stockholders’ equity $ 976,044 $ 913,850 $ 938,752 $ 667,323 $ 722,504 $ 715,614 $ 703,605 $ 672,698 Less: Average goodwill 128,679 131,302 95,696 34,153 34,366 26,824 26,741 26,741 Less: Average other intangible assets, net 48,950 51,495 40,918 16,242 16,775 3,172 3,211 3,424 Average tangible common equity 798,415 731,053 802,138 616,928 671,363 685,618 673,653 642,533 ROATCE 12.34 % 16.00 % 8.03 % 13.86 % 12.49 % 16.39 % 15.89 % 17.31 % Adjusted ROATCE 12.29 16.50 15.38 14.27 12.77 13.97 15.89 17.31 1Q21 4Q20 3Q20 2Q20 1Q20 4Q19 3Q19 2Q19 Net income $ 25,513 $ 17,552 $ 13,095 $ 4,957 $ 753 $ 12,827 $ 14,617 $ 12,283 Divided by number of days in the quarter 90 92 92 91 91 92 92 91 Multiplied by number of days in the year 365 366 366 366 366 365 365 365 Annualized net income $ 103,469 $ 69,826 $ 52,095 $ 19,937 $ 3,029 $ 50,890 $ 57,991 $ 49,267 Adjusted net income $ 25,470 $ 17,374 $ 12,857 $ 4,957 $ 461 $ 12,827 $ 13,782 $ 11,993 Divided by number of days in the quarter 90 92 92 91 91 92 92 91 Multiplied by number of days in the year 365 366 366 366 366 365 365 365 Annualized adjusted net income $ 103,295 $ 69,118 $ 51,149 $ 19,937 $ 1,854 $ 50,890 $ 54,679 $ 48,104 Total average common stockholders’ equity $ 657,863 $ 639,508 $ 629,533 $ 617,898 $ 611,162 $ 597,925 $ 588,504 $ 576,761 Less: Average goodwill 26,741 26,741 26,741 26,741 26,741 26,741 26,741 26,741 Less: Average other intangible assets, net 3,651 3,889 4,128 4,395 4,690 4,990 5,288 4,308 Average tangible common equity 627,471 608,878 598,664 586,762 579,731 566,194 556,475 545,712 ROATCE 16.49 % 11.47 % 8.70 % 3.40 % 0.52 % 8.99 % 10.42 % 9.03 % Adjusted ROATCE 16.46 11.35 8.54 3.40 0.32 8.99 9.83 8.81 32 DOLLARS IN THOUSANDS, UNAUDITED RECONCILIATION OF NON-GAAP FINANCIAL MEASURES

RECONCILIATION OF NON-GAAP FINANCIAL MEASURES DOLLARS IN THOUSANDS, UNAUDITED Calculation of Adjusted Efficiency Ratio: 1Q23 4Q22 3Q22 2Q22 1Q22 4Q21 3Q21 2Q21 Total noninterest expense $ 56,760 $ 57,254 $ 56,241 $ 44,150 $ 42,774 $ 40,346 $ 39,165 $ 37,832 Less: Insurance and mortgage noninterest expense 8,033 8,031 8,479 8,397 8,626 6,580 6,688 6,964 Less: Merger and acquisition expense — 1,179 3,614 807 571 — — — Adjusted total noninterest expense 48,727 48,044 44,148 34,946 33,577 33,766 32,477 30,868 Net interest income 77,147 84,749 78,523 59,504 52,502 54,180 52,541 54,292 Less: Insurance and mortgage net interest income 1,493 1,376 1,208 1,082 875 946 1,048 979 Add: Total noninterest income 16,384 13,429 13,723 14,216 15,906 16,701 15,923 12,438 Less: Insurance and mortgage noninterest income 8,792 6,255 4,737 8,047 10,552 5,683 6,179 5,815 Less: Gain on fair value of the Lincoln Agency — — — — — 5,213 — — Less: Gain on sale of securities, net 144 — 1,664 — — 75 — 5 Adjusted total revenue 83,102 90,547 84,637 64,591 56,981 58,964 61,237 59,931 Efficiency Ratio 60.69 % 58.32 % 60.97 % 59.89 % 62.53 % 56.92 % 57.21 % 56.69 % Adjusted Efficiency Ratio 58.64 53.06 52.16 54.10 58.93 57.27 53.03 51.51 1Q21 4Q20 3Q20 2Q20 1Q20 4Q19 3Q19 2Q19 Total noninterest expense $ 39,436 $ 38,884 $ 38,734 $ 38,220 $ 36,097 $ 36,534 $ 35,064 $ 37,095 Less: Insurance and mortgage noninterest expense 7,252 7,195 7,746 7,944 6,463 6,432 6,435 6,343 Less: Early termination of LT FHLB advance 1,613 — — — — — — — — — — — — Less: FDIC fund assessment benefit — — — — — — (1,037) — Adjusted total noninterest expense 30,571 31,689 30,988 30,276 29,634 30,102 29,666 30,752 Net interest income 55,239 51,819 50,617 46,290 42,810 44,095 44,622 42,969 Less: Insurance and mortgage net interest income 1,003 1,236 1,125 1,204 872 735 776 457 Add: Total noninterest income 17,131 15,381 18,051 19,076 12,144 10,818 12,880 11,176 Less: Insurance and mortgage noninterest income 8,348 9,326 12,741 13,826 6,456 5,787 6,295 6,288 Less: Gain on sale of securities, net 1,668 225 301 — 54 — 20 — Less: Other noninterest income(25) — — — — — 316 — — 367 Adjusted total revenue 61,351 56,413 54,501 50,336 47,256 48,391 50,411 47,033 Efficiency Ratio 54.49 % 57.86 % 56.41 % 58.47 % 65.69 % 66.53 % 60.98 % 68.51 % Adjusted Efficiency Ratio 49.83 56.17 56.86 60.15 62.71 62.21 58.85 65.38 33 ORIGIN BANCORP, INC. _______ * Please see slide 34 for all footnote references included above.

34 PRESENTATION NOTES (1) Does not include non-market based deposits. (2) Excludes mortgage warehouse loans. (3) As used in this presentation, adjusted net income, adjusted PTPP earnings, adjusted diluted EPS, adjusted ROAA, adjusted PTPP ROAA, adjusted ROAE, adjusted PTPP ROAE, tangible book value per common share, adjusted tangible book value per common share, tangible common equity to tangible assets, ROATCE, adjusted ROATCE and adjusted efficiency ratio are either non-GAAP financial measures or use a non-GAAP contributor in the formula. For a reconciliation of these alternative financial measures to their comparable GAAP measures, see slides 24-33 of this presentation. (4) NIM - FTE, adjusted, is calculated for the quarter ended March 31, 2023, December 31, 2022 and September 30, 2022, by removing the net purchase accounting accretion from the net interest income. For periods prior to September 30, 2022, it is calculated by removing average PPP loans from average interest-earning assets and removing the associated interest income (net of 35 basis points assumed cost of funds on average PPP loan balances) from net interest income. (5) An increase in accumulated other comprehensive loss negatively impacted total stockholders' equity, tangible common equity, book value and tangible book value per common share primarily due to the movement of the short end of the yield curve that occurred during the first three quarters of 2022 and its impact on our investment portfolio. (6) The ALCL to total LHFI, adjusted is calculated at March 31, 2023, December 31, 2022 and September 30, 2022, by excluding the ALCL for warehouse loans from the total LHFI ALCL in the numerator and excluding the warehouse loans from the LHFI in the denominator. For the periods prior to September 30, 2022, it is calculated by excluding the ALCL for warehouse loans from the total LHFI ALCL in the numerator and excluding the PPP and warehouse loans from the LHFI in the denominator. Due to their low-risk profile, mortgage warehouse loans require a disproportionately low allocation of the ALCL. (7) Total LHFI, adjusted excludes mortgage warehouse loans for all periods presented and PPP loans for periods prior to September 30, 2022. (8) Annualized. (9) A decline in accumulated other comprehensive loss during the YTD period ended December 31, 2022, negatively impacted total stockholders' equity, tangible common equity and ROATCE, primarily due to the steepening of the short end of the yield curve that occurred during the first three quarters of 2022 and its impact on our investment portfolio. (10) OBNK and KBW Nasdaq cumulative total shareholder return assumes $100 Invested on December 31, 1996, and any dividends are reinvested. Data for OBNK cumulative total shareholder return prior to May 9, 2018, is based upon private stock transactions and is not reflective of open market trades. (11) Data obtained from The United States Census Bureau (census.gov). (12) Excludes mortgage warehouse loans and, for all periods prior to 3Q22, PPP loans. (13) Year-to-date periods ended December 31, 2021 and 2020 exclude PPP loans. (14) Does not include loans held for sale. (15) PPP loans are immaterial at 1Q23, 3Q22 and 4Q22 and are included in C&I for these periods. (16) Excludes PPP loans for the quarters ended March 31, 2022, and June 30, 2022. (17) The accumulated other comprehensive (loss) income primarily represents the unrealized loss, net of tax benefit, of available for sale securities and is a component of equity. (18) Peer represents commercial banks as identified by S&P Global. (19) Yield on LHFI excl. PPP loans and purchase accounting adjustments ("PAA") reflects the exclusion of PPP loans for periods prior to 3Q22 and the exclusion of PAA for 1Q23, 4Q22 and 3Q22. (20) LIBOR index-based loans will shift to SOFR index-based loans at the end of 2Q23. (21) Net interest income excl. MW LOC, adjusted, and NIM (FTE), adjusted, excludes PPP income from periods prior to 3Q22, and PAA net accretion for 1Q23, 4Q22 and 3Q22. (22) Mortgage banking revenue for 3Q22 was adjusted for the $1.95 million impairment on the GNMA MSR portfolio. (23) March 31, 2023, dollars and ratios are estimated. (24) 3Q22 does not include BTH Bank, which elected the Community Bank Leverage Ratio. (25) Other noninterest income represents a $316,000 payout on a BOLI life insurance policy during 1Q20 and a $367,000 valuation adjustment on a non-marketable equity security during 2Q19.