Colin Kaepernick is a hero to ex-convicts and men still behind bars ... so says a community organizer who Colin blessed with a huge donation. 

TMZ Sports spoke with Kevin Livingston of 100 Suits For 100 Men, a NYC based company that provides free outfits, haircuts and life skills to men who have been incarcerated at least 5 years.

Kevin says Kaep's girlfriend Nessa put the two men in touch after doing an interview with Hot 97 ... and the NFL QB couldn't have been more generous ... personally delivering 50 custom suits to the organization. 

"He was a great partner," Livingston says. "He went above and beyond all expectations to help give these guys a second chance."

"He's a hero in my eyes, he's a hero in the eyes of the guys who are going to be receiving these suits. Colin you're the man to me, you're a hero to the men of South Jamaica Queens."

Kevin also had a message for all the Kaepernick haters out there.

"What are you doing?"