I found this on the Classic Marvel site ... I don't like using it cause their bios aren't the best but maybe we could expand on this...
History:
Sam Wilson is the son of a dedicated and influential minister in Harlem who died trying to stop a street fight. Sam idolized his father and tried to emulate his selfless humanitarianism after his death. But when his mother was killed by a mugger two years later, Sam's grief and anger consumed him. Severely depressed, Sam Wilson's personality changed. No longer was he a concerned community volunteer, but a self-serving racketeer who called himself "Snap". En route from a mob assignment in Rio de Janeiro, Wilson's plane crashed on the Caribbean Island run by the Exiles, and band of professional killers who were accomplices of the Red Skull. The Skull used the powers of the Cosmic Cube to transform "Snap" back into Sam, in order to use him as a pawn against Captain America, who was at that time trapped on the island. The Skull reasoned that Wilson's former idealism would appeal to the Captain enough that he would train him as a partner. Then, at some later date, the Skull could use him against his enemy if his current attack failed.
