v3.25.2
Document and Entity Information - shares
6 Months Ended
Jun. 30, 2025
Aug. 14, 2025
Cover [Abstract]    
Document Type 10-Q  
Amendment Flag false  
Document Quarterly Report true  
Document Period End Date Jun. 30, 2025  
Current Fiscal Year End Date --12-31  
Document Fiscal Year Focus 2025  
Document Fiscal Period Focus Q2  
Document Transition Report false  
Entity File Number 814-01399  
Entity Registrant Name Star Mountain Lower Middle-Market Capital Corp  
Entity Central Index Key 0001786835  
Entity Incorporation, State or Country Code DE  
Entity Tax Identification Number 86-3924884  
Entity Address, Address Line One 140 E. 45th Street  
Entity Address, Address Line Two 37th Floor  
Entity Address, City or Town New York  
Entity Address, State or Province NY  
Entity Address, Postal Zip Code 10017  
City Area Code 212  
Local Phone Number 810-9044  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Filer Category Non-accelerated Filer  
Entity Small Business false  
Entity Emerging Growth Company true  
Entity Ex Transition Period false  
Entity Shell Company false  
Entity Common Stock, Shares Outstanding   10,026,043