Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2021	Mar. 31, 2022	Jun. 30, 2021
Entity Listings [Line Items]
Document Type	10-K
Amendment Flag	false
Document Annual Report	true
Document Period End Date	Dec. 31, 2021
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY
Document Transition Report	false
Entity File Number	001-39523
Entity Registrant Name	North Mountain Merger Corp.
Entity Central Index Key	0001819157
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	83-1960216
Entity Address, Address Line One	767 Fifth Avenue, 9th Floor
Entity Address, City or Town	New York
Entity Address, State or Province	NY
Entity Address, Postal Zip Code	10153
City Area Code	646
Local Phone Number	446-2700
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	true
Entity Public Float			$ 0
Auditor Name	Marcum LLP
Auditor Location	Los Angeles, CA
Auditor Firm ID	688
Units [Member]
Entity Listings [Line Items]
Title of 12(b) Security	Units, each consisting of one share of Class A common stock, $0.0001 par value, and one-half of one warrant
Trading Symbol	NMMCU
Security Exchange Name	NASDAQ
Class A Common Stock [Member]
Entity Listings [Line Items]
Title of 12(b) Security	Shares of Class A common stock
Trading Symbol	NMMC
Security Exchange Name	NASDAQ
Entity Common Stock, Shares Outstanding		13,225,000
Warrants [Member]
Entity Listings [Line Items]
Title of 12(b) Security	Warrants
Trading Symbol	NMMCW
Security Exchange Name	NASDAQ
Class B Common Stock [Member]
Entity Listings [Line Items]
Entity Common Stock, Shares Outstanding		3,306,250