Humphrey grew up watching the Sooners and wrestling like his father, Chad, who grappled at the University of Central Oklahoma. The first-team all-state pick at Shawnee High School redshirted in 2017 before taking over the starting center spot in 12 of 14 games played in 2018, when he earned Freshman All-American and honorable mention All-Big 12 honors while helping the front five win the Joe Moore Award as the nation's top offensive line. Humphrey sat out spring 2019 practices due to injury but was ready for the fall, garnering Rimington Trophy finalist, second-team Associated Press All-American and Big 12 Co-Offensive Lineman of the Year accolades as a 14-game starter. The 2020 team captain and 11-game starter was named a third-team AP All-American, Big 12 Offensive Lineman of the Year and first-team all-conference center as a junior. He accepted an invitation to the Senior Bowl.