Previously, Coombs was an assistant coach for the Tennessee Titans of the National Football League (NFL) in 2018 and 2019 and the defensive coordinator for the Ohio State Buckeyes from 2020 to 2021.

Coombs was a member of the University of Dayton's 1980 Division III National Championship team while studying secondary education.

[3] In 2007, Coombs accepted the offer from Brian Kelly to join his staff at the University of Cincinnati as the team's defensive backs coach.

In 2017, Ohio State head coach, Urban Meyer, promoted Coombs to the position of assistant coordinator, defense.

In 2020, Ohio State needed to fill the position of defensive coordinator and secondary coach following the retirement of Greg Mattison.

[15] Following Ohio State's week 3 victory over Tulsa, a game where the Buckeyes again allowed over 500 total yards of offense,[16] head coach Ryan Day announced that secondary coach Matt Barnes had called the defensive plays that week, rather than Coombs.

This ultimately led to Coombs and Ohio State agree to part ways after the season ended.

On January 18, 2022, it was reported that Coombs was returning to the University of Cincinnati as cornerbacks coach and special teams coordinator.

[19] On November 27, 2022, following the announcement of Fickell's hire by Wisconsin,[20] Coombs was promoted to interim head coach for the remainder of the Bearcats' season.