High School: A sprinter from Hanford High School, Stewart’s best event in high school was the 100 meters, with a personal best of 11.04 during his senior year. Stewart was named athlete of the meet at the Prosser Rotary Invitational after a second-place finish in the 100 and anchoring his 4x100-meter relay to a win. Stewart was named first team all-conference for the 4x100-meter relay and the 100 meters. He was also named second team all-conference in the 200 meters with a best time of 22.68. He lettered in track and football.