As a young man, McCree had already made a name for himself as a member of the notorious Deadlock Gang, which trafficked in illicit weapons and military hardware throughout the American Southwest, when he and his associates were busted in an Overwatch sting operation. With his expert marksmanship and resourcefulness, he was visited by Gabriel Reyes, the head of Overwatch's Blackwatch covert ops division. Reyes gave him the choice between rotting in a maximum security lockup or joining Blackwatch. McCree chose the latter.

Although he was initially cynical, he came to believe that he could make amends for his past sins by righting the injustices of the world. McCree appreciated the flexibility afforded to the clandestine Blackwatch, unhindered by bureaucracy and red tape. He was given instruction by Reyes.