Horton has a long history with head coach Ken Whisenhunt. The two worked together with the Pittsburgh Steelers and Arizona Cardinals. Horton was the secondary coach of the Steelers from 2004-10, helping the team win two Super Bowl titles in that span. He followed Whisenhunt to Arizona in 2011 and was the defensive coordinator for two years. After the Cardinals fired Whisenhunt, Horton took the defensive coordinator job with the Cleveland Browns. He lasted just one year, leaving the team when Rob Chudzinski got fired.
Horton is considered one of the top defensive minds in the league. He's best known for his 3-4 defense, but is expected to run more of a hybrid system in Tennessee. During his two years in Arizona, the Cardinals fielded one of the best defenses in football. The Browns were less successful in his one year there, but they ranked ninth in yards allowed and eighth in points allowed.
Horton inherits a promising unit in Tennessee. After giving up the most points in the league in 2012, the Titans allowed the fewest touchdowns in football last season, led by breakout stars like cornerback Alterraun Verner and free agent signee safety Bernard Pollard.