He went to Bakersfield College for a year and played on the football team before serving in the United States Air Force for the Korean War.

He compiled a 61–26–2 record and won three conference titles, ranking second in Aztec victories and winning percentage only to Coryell.

[5] During a transition from relying on junior college transfers to recruiting high school students, the Aztecs went 4–8 in 1980 and fired Gilbert in a controversial move.

Gilbert was fired from San Jose State following the 1989 season after signing 21 junior college transfers, against orders from administration to limit scholarships offered to such student-athletes.

[8][9] Gilbert returned to San Diego State as defensive coordinator under Ted Tollner in 1995, and oversaw consecutive eight-win seasons, which was not achieved until 2010 and 2011.