Harper was born on November 5, 2000, in Knoxville, Tennessee.[1] He grew up playing basketball before trying out for the Karns High School football team as a sophomore.[2] With the Karns football team, he became a top wide receiver and defensive back.[2] He was an all-district, all-region and team MVP selection while being the first player in school history with over 1,000 receiving yards.[3]
Harper appeared in 12 games as a true freshman in 2019, mainly on special teams, recording 13 tackles.[1] The following year, he appeared in all 11 games, one as a starter, and recorded 31 tackles while earning second-team Academic All-Big 12 Conference honors.[1] In 2021, he played 12 games and totaled 20 tackles with 1.5 tackles-for-loss (TFLs).[6] He won a starting role in 2022.[7] That year, he made 30 tackles and 1.5 TFLs while appearing in seven games.[1]
In 2023, Harper transferred to the Notre Dame Fighting Irish for his final season of eligibility.[8] With Notre Dame, he appeared in 11 games and posted 39 tackles, six TFLs, three passes defended and two sacks.[9] He opted out of the team's 2023 Sun Bowl victory over Oregon State due to injury.[10]