Claeys was the defensive coordinator at Washington State University from 2018 to 2019 and the linebackers coach at Virginia Tech in 2020.
After graduating with a degree in Mathematics Education in 1994 from Kansas State, he was hired at Santa Fe Trail High School as a math teacher and co-defensive coordinator of the football team.
When Kill took the head coaching job at Emporia State in 1999, Claeys followed and was promoted to defensive coordinator.
He also coached four First Team All-Big Ten defensive selections—Briean Boddy-Calhoun (2014), Damien Wilson (2014), Ra'Shede Hageman (2013), and Brock Vereen (2013)—at Minnesota in five years.
On October 10, 2013, it was announced that Kill would take an open-ended leave of absence from coaching to focus on treating his epilepsy.
Kill retired for health reasons on October 28, 2015, and Claeys was named interim head coach for the remainder of the season.
[4] On November 11, 2015, Minnesota dropped the "interim" tag from Claeys' title and formally named him as its 29th head coach.
[5] On January 3, 2017, he was fired after public outrage over a team-led boycott in response to suspensions of 10 Minnesota football players accused of having a role in a sexual assault case.
He resigned on October 4, 2019; at the time, Washington State's defense was ranked 107th in the nation and was allowing over 30 points per game.