Clark started for the Red Raiders for the first time during his redshirt freshman year at the right guard position.

For his performance during the season, Clark was named a Freshman All-American by the Football Writers Association of America and Scout.com.

During his sophomore year in 2013, Clark was moved to left tackle to replace All-Big 12 and current New England Patriots player LaAdrian Waddle.

Prior to the beginning of the season, Clark was named a pre-season All-Big 12 selection, and was placed on the watchlists for the Outland Trophy and the Lombardi Award.

[6] Following the conclusion of the season, Clark earned Associated Press All-Big 12 1st team honors.

[7] Prior to the 2014 season, Clark was again named to the Outland Trophy and Lombardi Award watchlist.

[18][19] He was promoted to the active roster on December 8 and signed a contract extension that runs through the 2022 season.