Warmack attended Westlake High School in Atlanta, Georgia, where he was an all-state offensive lineman. For his freshman and sophomore year, he was a teammate of Cam Newton. Rated as a three-star recruit by Rivals.com, Warmack was ranked as the No. 20 offensive guard prospect in his class.
As a junior in 2011, he started 13 more games and helped Alabama win the 2012 BCS National Championship Game over Louisiana State, while earning 2nd team All-SEC honors. After weighing his options to enter the 2012 NFL Draft, Warmack decided to return to Alabama for his final year of eligibility. Prior to his senior season, he received numerous individual accolades, being on multiple preseason award watch lists and being named to Sports Illustrated's preseason All-American team.
Warmack started all 13 games for the Crimson Tide as a senior.