Born in Eugene, Oregon, Ainge starred in high school on his football team and led North Eugene High School to back-to-back state basketball championships in 1976 and 1977, earning all-state honors both years; he was considered one of the top prep football recruits in the state of Oregon.
Ainge played basketball at Brigham Young University (BYU) and became a household name after hitting one of the best-known shots in NCAA March Madness history against Notre Dame in 1981.