In December 2007, Dunn was enlisted as defensive coordinator at
New Mexico State University, serving under head coach
Hal Mumme, who compiled a 7–29 record. In December 2008, Mumme was fired, and was later hired as head coach of McMurry University in Texas. Dunn joined Mumme's staff in April 2009 at the Division III school, and served as defensive coordinator through the 2012 season. From 2006 until 2007, he was the head football coach at
Ridgeway High School in
Memphis, Tennessee. From 2003 until 2005, he was the defensive coordinator of the
Memphis Tigers football program. He transformed the Tigers defense from a unit that ranked near the bottom statistically in defense, to a top 25 defensive unit. Prior to coaching at Memphis, he was the defensive coordinator at
Mississippi State from 1996 to 2002. In 1995, he served as the defensive coordinator at
Arkansas, helping the Razorbacks win their first SEC Western Division championship that season. In 1999, while serving as defensive coordinator and linebackers coach at Mississippi State, Dunn was a finalist for the
Broyles Award, given annually to the nation's top college football assistant coach. "He came to Starkville prior to the 1996 season and inherited a defense that had just finished the year before ranked 12th in the Southeastern Conference. By 1999, the Bulldog defense was first in not only their league, but the entire country." From 1992 to 1994, he served as the defensive coordinator at
Mississippi. After
Billy Brewer was fired just before the 1994 season, Dunn was named head coach and led the Rebels to a 4–7 record. From 1987 to 1988, he had served as
South Carolina's defensive coordinator. From 1983 to 1986, he was the head football coach at
New Mexico, where he compiled a 17–30 record. ==Death==