Cain began his coaching career as a high school coach. He then went on to work as an assistant coach at Sacramento City College. In 2005 he got his first opportunity at the FBS level as a graduate assistant under Frank Solich at Ohio. From 2006 to 2008 he worked as the defensive ends coach for Missouri State. From 2009 to 2012 he was the defensive line coach for Cal Poly.
In 2013 he served as the defensive line coach for Wyoming. He was promoted to defensive coordinator midway through the season.[1]
Cain spent three seasons as the defensive ends coach at North Dakota State before taking a defensive line position at San Jose State. He was part of NDSU's fourth and fifth straight FCS national championships in 2014 and 2015 and the team's sixth consecutive Missouri Valley Football Conference title in 2016.
Cain helped in developing 2014 Buck Buchanan Award winner and consensus All-American Kyle Emanuel, who had 19.5 sacks and 32.5 tackles for loss his senior year and was a fifth round NFL draft pick. He also coached All-American Greg Menard, a nominee for the 2016 Buck Buchanan Award.
After originally taking a job at San Jose State.[2] In 2017 and 2018 he worked as the defensive line coach for Fresno State.
In 2019 he worked as the defensive line coach for ASU.[3] With Cain on staff, ASU's 2019 run defense was significantly better than the year before he arrived. It ranked 26th nationally in 2019 by allowing 125.1 rushing yards per game, and 24th by permitting 3.5 yards per carry. In 2018, before he was on staff, ASU ranked 74th and 66th, respectively, at 170.5 and 4.3.
In 2020 and 2021 he worked as the outside linebackers and defensive ends coach for the Sooners.[4]
After originally following Lincoln Riley to USC.[5] Cain decided to join Brian Kelly's inaugural LSU staff as the defensive line coach and defensive run game coordinator.[6][7]
Cain was hired on March 25, 2023 as a pass rushing specialist for the Denver Broncos.[8] He was promoted to defensive line coach after Marcus Dixon left to take the same job with the Minnesota Vikings.[9]