James was a starter for St. Vincent-St. Mary's varsity basketball team since his freshman year. During this year, he averaged 21 points and 6.2 rebounds per game, eventually leading the Irish to the Ohio High School Athletic Association (OHSAA) Division III state title. The next year, he upped his averages to 25.2 points and 7.2 rebounds per game, while also contributing 5.8 assists and 3.8 steals per game.