[2] He served as an assistant at Gaffney through the 1978 season before taking the defensive coordinator position at Spartanburg High School in 1979.
[4] After three years at Clemson, Johnson returned to Alabama in January 1997 to serve as defensive coordinator for head coach Mike DuBose.
[6] After his three-year tenure with The Citadel, Johnson served as defensive coordinator at both Mississippi State (2004–2007) and South Carolina (2008–2011).
While serving at South Carolina the Gamecocks won the SEC East Division championship for the first time in school history in 2010, clinching the title with a convincing 36–14 victory over the Florida Gators.
1 ranked team (Alabama), and first time sweeping the November "Orange Crush" portion of their schedule with wins over Tennessee, Florida and Clemson.
In late November 2014, reports began to surface on the internet claiming that Johnson's employment with Auburn University had been terminated.
[9] Johnson returned to South Carolina in 2016, hired by head coach Will Muschamp to serve as an analyst until leaving that position in 2018.
[12] After serving three seasons as defensive coordinator at Alabama, on December 21, 2000, Johnson was named head coach at The Citadel, The Military College of South Carolina.
"[17] He signed a four-year contract on August 20, 2012 (twelve days before the start of the 2012 season) that paid him a minimum of $740,000 annually, and was to run through December 23, 2015.
[18] Prior to Johnson's tenure, the Southern Miss football team had recorded eighteen straight winning seasons and been to ten consecutive postseason bowl appearances.
In 2011, under Coach Larry Fedora, the Golden Eagles won a school record 12 games and finished in the Top 20 of both major polls after a victory in the 2011 Hawaii Bowl.