After Long's successor Darrell Dickey left for Texas A&M, Dillingham was promoted to offensive coordinator for the 2018 season.
[4] Dillingham was hired by Gus Malzahn to be the offensive coordinator and quarterbacks coach at Auburn in 2019, replacing Chip Lindsey.
[11] On November 27, 2022, Dillingham was named the 26th head coach at Arizona State University, replacing Herm Edwards.
In his second season, Dillingham's team was projected to finish last in the Big 12 according to the conference’s preseason media poll.
[13] However, they exceeded expectations, winning the Big 12 Championship game by defeating Iowa State and earning a first-round bye in the 2024 College Football Playoff.