[3] Harper accepted a football scholarship from Oklahoma State University, with the intention of playing linebacker.
As a sophomore in 2018, he appeared in all 13 games with one start, recording 44 total tackles (5 for loss), 2.5 sacks, one pass defensed, one forced fumble and an interception returned for a touchdown.
Harper played through a painful junior year in 2019, wearing a cast during a part of the season.
As a super senior in 2021, he enjoyed his best season, becoming a full-time starter along with being voted a team captain.
[7] In the 2021 Bedlam matchup against Oklahoma, he was a key part in defending their offense, tying a career-high 10 tackles (7 solo), and with less than 2 minutes left in the game, he forced a throwaway pass, a 5-yard loss sack, tackled quarterback Caleb Williams short of the first down marker on three consecutive plays, while helping the Cowboys close a 37-33 win.
[8] He had 10 tackles in the 2022 Fiesta Bowl, contributing to one off the biggest rallies in school history for a 37-35 win against the University of Notre Dame.
In 2023, after rookie DeMarvion Overshown's season-ending injury, Markquese Bell passed him on the depth chart for the strongside linebacker job.
He was waived by the team on September 28, to make room for center Brock Hoffman, in order to provide depth on the offensive line.