Trevor Keegan attended Crystal Lake South High School where he helped the Gators reach IHSA Playoffs in his freshman and senior seasons, with an appearance in the second round in 2018. He chose to join Michigan after his high school career.
Keegan did not play in his first season, redshirting heading into his sophomore year. In his second year, he appeared in 5 games, mostly on special teams, with two games on the offensive line.
In his junior season, he made his first campaign as a starter, appearing in 13 games with 11 starts at left guard.
In his final college season in 2023, he started all 15 games at left guard, earning 5 offensive player of the week awards as he was consistently one of the best players on the field.