Gunn was a 1969 All-American defensive end at the University of Southern California.

In 1969, he teamed with All-Americans Al Cowlings, Charlie Weaver, Tody Smith, and Bubba Scott to form a defensive front that powered the Trojans to 10–0–1 record and a win over the University of Michigan in the 1970 Rose Bowl.

Coach John McKay credited a six-man front on defense for the victory, big Tony Terry was added to the group known as the "Wild Bunch" consisting of Jimmy Gunn, Charlie Weaver, Al Cowlings, Tody Smith and Bubba Scott.

[1] Gunn played professionally for the Chicago Bears, New York Giants and Tampa Bay Buccaneers between 1970 and 1976.

This biographical article relating to an American football linebacker born in the 1940s is a stub.