After two years as the offensive coordinator and line coach there, he moved to the college ranks and started working as a graduate assistant under Ken Hatfield at Rice in 1995.
After Crowton resigned following the 2004 season, newly promoted head coach Bronco Mendenhall decided to keep Grimes on his staff.
The 2006 BYU linemen Grimes coached blocked for the nation's fourth best offense, averaging over 465 yards per game including 141.9 on the ground, and were a large part of the Cougars winning the Mountain West Conference championship.
[3] At the end of the 2012 season, Chizik was fired by Auburn, with former offensive coordinator, Gus Malzahn, hired as head coach on December 4, 2012.
The news was unofficially released on January 15, 2014, and later confirmed by Virginia Tech's running backs coach, Shane Beamer.
[6][7] In December 2017, Grimes was named the offensive coordinator at BYU, under head coach Kalani Sitake, replacing Ty Detmer.
[9] On January 4, 2021, Grimes was named the offensive coordinator at Baylor under head coach Dave Aranda, replacing Larry Fedora.
[11] Kansas hired Grimes in December 2023 as offensive coordinator and assistant head coach under Lance Leipold.