He attended segregated all-Black schools in St. Louis, including Lincoln High School, although he never graduated. His uncle and aunt provided him with a stable upbringing, but after his uncle died in a freak accident around 1928, Moore began running with a street gang. One of his first thefts was a pair of oil lamps from his home, which he sold so that he would have money to buy boxing gloves. He later recalled of his stealing: "It was inevitable that I would be caught. I think I knew this even before I started, but somehow the urge to have a few cents in my pocket made me overlook this eventuality". After he was arrested for attempting to steal change from a motorman's box on a streetcar, he was sentenced to a three-year term at a reform school in Booneville, Missouri. He was released early from the school for good behavior after serving twenty-two months.