Mitchell played in all 14 of the Ragin' Cajuns' games as a freshman. He was named a starter going into his sophomore year and started every game for Louisiana. Mitchell started at both left and right tackle as a junior and was named second-team All-Sun Belt Conference. As a senior, he was named first-team All-Sun Belt and a third-team All-American by the Associated Press. After the season, Mitchell received invitations to play in the Senior Bowl and participate in the NFL Combine.