Although a new character, it is implied that Sal Kennedy met, and befriended Tony Stark at some point in his early twenties; most likely at the same emergent tech conference that Tony met Maya Hansen.
Sal Kennedy was created by Warren Ellis and Adi Granov and first appeared in Iron Man #2 (2005).
Mayor Story Arcs
Throughout the first 17 issues of The Invincible Iron Man, Sal was often sought out by Tony for advice and guidance, aiding Tony through several crises. He even helped Tony out during the extreme situation of the superhuman Civil War. Eventually Sal takes a position working for SHIELD under Tony despite his more hippy attitude toward such organizations.
Sal was killed when the Helicarrier came under attack by a genetically engineered neoplastic tumor (AKA a giant flesh absorbing monster). A attack later revealed to be the doing of The Mandarin.
Iron Man 3
Sal Kennedy's role in Iron Man 3 will be different from his comic book version. It seems Sal Kennedy will probably be a member of the Kennedys who becomes the next president of the United States rather than Tony's mentor.