James grew up with his strict father who was a strict Christian minister but the boy was an unstoppable dreamer wishing to travel. The latter was inspired by his upstairs neighbor 'Smiley', a jazz singer who died slowly and lonely. Jim was shaken as he was very young and never wanted to die old and lingering like that. He quit school at 15 to go for an adventure which resulted a violent argument with his dad. Going immediately to Los Angeles he ended up a hobo claiming he was an LA native whose parent died in fire and living in an abandoned building. Jim even thought his story was true and started doing petty crimes but mostly felt sorry and undid the actions.
Hulk sought refuge in his abandoned tenement while wanted and bonded with Jimmy who later helped him a lot in life against his greatest enemies. Jim became an ally of the US army to calm the Hulk threat and started a relationship with Talia Green who disliked Hulk. He became involved in many superhero activities and trouble due to this friendship.
Jim Wilson was the nephew of Sam "Snap" Wilson, the superhero also know as Falcon. Wilson, being HIV positive has to deal with stereotypes by homophobics and bigots. It is never explained how Wilson got HIV, just that his girlfriend Talia had left him. He became a manager in a clinic for AIDS patients. Soon after developing full-blown AIDS, Wilson is on his death bed. Wilson asks Hulk for a blood tranfusion, knowing that the Hulk's blood would cure the disease. Hulk, not wanting to create another monster, pretends to give the transfusion to Wilson. Soon after Wilson admits it would not have been a good idea. Banner donated money to the clinic to survive for a decade.
Poor Wilson was charismatic and funny, knowing stuff about many American towns due to hitch-hiking and Betty Ross taught him to play chess, he was a friend to her father too.
Jim makes a cameo appearance in The Incredible Hulk, portrayed by P.J. Kerr. He is shown as a student at the university where Bruce Banner goes on a rampage, and is interviewed after the incident. His uncle Sam appears in Captain America: The Winter Soldier, portrayed by Anthony Mackie.