<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2022-09-14</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001674930</issuerCik>
        <issuerName>Fulgent Genetics, Inc.</issuerName>
        <issuerTradingSymbol>FLGT</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001302110</rptOwnerCik>
            <rptOwnerName>Hsieh Ming</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O FULGENT GENETICS, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>4978 SANTA ANITA AVENUE</rptOwnerStreet2>
            <rptOwnerCity>TEMPLE CITY</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>91780</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chief Executive Officer</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001836339</rptOwnerCik>
            <rptOwnerName>Ming Hsieh Trust</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O FULGENT GENETICS, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>4978 SANTA ANITA AVENUE</rptOwnerStreet2>
            <rptOwnerCity>TEMPLE CITY</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>91780</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>30000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>7895115</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Trust</value>
                    <footnoteId id="F1"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Uniform Transfer to Minors Account</value>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Uniform Transfer to Minors Account</value>
                    <footnoteId id="F3"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Forward sale contract (obligation to sell)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F4"/>
                <footnoteId id="F5"/>
                <footnoteId id="F6"/>
                <footnoteId id="F7"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2022-09-14</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>1</equitySwapInvolved>
                <footnoteId id="F4"/>
                <footnoteId id="F5"/>
                <footnoteId id="F6"/>
                <footnoteId id="F7"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>800000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F4"/>
                    <footnoteId id="F5"/>
                    <footnoteId id="F6"/>
                    <footnoteId id="F7"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F4"/>
                <footnoteId id="F5"/>
                <footnoteId id="F6"/>
                <footnoteId id="F7"/>
            </exerciseDate>
            <expirationDate>
                <value>2026-09-01</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>800000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>800000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Trust</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F4"/>
                    <footnoteId id="F5"/>
                    <footnoteId id="F6"/>
                    <footnoteId id="F7"/>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Securities held by The Ming Hsieh Trust. Mr. Hsieh is the trustee of The Ming Hsieh Trust (the &quot;Trust&quot;) and possesses the sole voting and dispositive power with respect to securities held by the Trust.</footnote>
        <footnote id="F2">Shares held in a Uniform Transfers to Minor Act account for which Ming Hsieh acts as custodian and possesses the sole voting and dispositive power.</footnote>
        <footnote id="F3">Shares held in a Uniform Transfers to Minor Act account for which Ming Hsieh acts as custodian and possesses the sole voting and dispositive power.</footnote>
        <footnote id="F4">On September 14, 2022, the Trust entered into a master confirmation in respect of a prepaid variable forward agreement (the &quot;Agreement&quot;) with an unaffiliated bank (the &quot;Bank&quot;) relating to 800,000 shares of Common Stock and obligating the Trust to deliver to the Bank up to 800,000 shares of Common Stock (or, at the Trust's election, an equivalent amount of cash) to settle the Agreement.</footnote>
        <footnote id="F5">In exchange for entering into the Agreement and assuming the obligations thereunder, the Trust received a cash payment of $28,955,274.40. The Trust pledged 800,000 shares of Common Stock (the &quot;Pledged Shares&quot;) to secure its obligations under the Agreement, and retained voting rights in the Pledged Shares during the term of the pledge (and thereafter if the Trust settles the Agreement in cash).</footnote>
        <footnote id="F6">Under the Agreement, on each of the eight settlement dates in September 2026, the Trust will be obligated to deliver to the Bank a number of shares of Common Stock determined as follows (or, at the Trust's election, an equivalent amount of cash): (a) if the closing price of the Common Stock on the related valuation date (the &quot;Settlement Price&quot;) is less than or equal to $41.0261 (the &quot;Floor Price&quot;), the Trust will deliver to the Bank 100,000 shares (i.e., the ratable portion of the Pledged Shares to be delivered with respect to each settlement date).</footnote>
        <footnote id="F7">(continued from footnote 6) (b) if the Settlement Price is between the Floor Price and $55.1572 (the &quot;Cap Price&quot;), the Trust will deliver to the Bank a number of shares of Common Stock equal to 100,000 shares multiplied by a fraction, the numerator of which is the Floor Price and the denominator of which is the Settlement Price: and (c) if the Settlement Price is greater than the Cap Price, the Trust will deliver to the Bank the number of shares of Common Stock equal to the product of (i) 100,000 shares and (ii) a fraction (a) the numerator of which is the sum of (x) the Floor Price and (y) the Settlement Price minus the Cap Price, and (b) the denominator of which is the Settlement Price.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Paul Kim as Attorney-in-Fact</signatureName>
        <signatureDate>2022-09-16</signatureDate>
    </ownerSignature>
</ownershipDocument>
