A native of Paducah, Kentucky, Bennett graduated from the University of Kentucky, playing at both quarterback and defensive back under head coach Blanton Collier for three seasons beginning in 1958. During Collier's final season with the Wildcats in 1961, Bennett began his coaching career by serving as an assistant coach with the team.
Bennett continued the following year under new head coach Charlie Bradshaw, then served in the military the next two years. In his first full year as a coach, Bennett was on the staff for Bradshaw's infamous first team that was known as the Thin Thirty. He resumed his career at Kentucky in 1965, then moved on to the University of Pittsburgh the following year. After only one year in the Steel City, Bennett accepted the offensive backs coaching position under Homer Rice at the University of Cincinnati in 1967, then was promoted to offensive coordinator the following year.
On February 7, 1969, Bennett assumed similar duties at the U.S. Naval Academy under Rick Forzano, but left on March 13, 1970 to become offensive backs coach with the NFL's St. Louis Cardinals (football). Bennett survived a coaching change after his first season, but left after the 1971 NFL season to become an assistant with the Detroit Lions.
After Chuck Knox was hired as head coach of the Los Angeles Rams in January 1973, he hired Bennett as the team's receivers coach. Over the next four years, the team's high-powered offense helped the team reach three NFC Championship games, but fell short of a Super Bowl berth. Despite coming up short, Bennett became a head coach for the first time when he was hired by the Falcons on February 3, 1977.
During his first season in Georgia, Bennett's defense became known as the "Grits Blitz" for its ferocious style and allowing just 129 points, a record for a 14-game season. The overall improvement of the team became evident the following year, when the Falcons defeated the Philadelphia Eagles in the NFC Wild Card game, then put up a strong fight against the defending Super Bowl champion Dallas Cowboys.
After the team endured a losing season in 1979, Bennett led the team to its first NFC West title and a then-team record 12 wins. However, a fourth quarter collapse against the Cowboys in the first round of the playoffs abruptly ended the season.
While another losing record followed in 1981, the team won its final three games, giving hopes of another comeback. However, the strike-shortened 1982 NFL season saw Bennett's team finish 5-4, reaching the postseason in the expanded playoff system, but losing the first round game to the Minnesota Vikings. A late season slump, coupled with the playoff losses and overall inconsistency, resulted in Bennett being dismissed on January 14, 1983. He was the first coach in team history to leave the team with a winning record, going 47-44 (including a 1-3 record in the playoffs). Jim Mora also left the team with a winning record, 26-22.
For the next two years, Bennett sold recreational vehicles before the Tampa Bay Buccaneers hired him on January 23, 1985, to replace the retiring John McKay. However, Bennett's previous success did not come with him to Tampa, with consecutive 2-14 finishes in both of his years as coach of the Bucs. On December 29, 1986, he was dismissed by team owner Hugh Culverhouse.
Bennett then returned to Atlanta, where he purchased a car dealership and was named chairman of the selection committee for the Peach Bowl. In 1991, Bennett sold the dealership and was hired as director of development for the Greater Atlanta Christian School, where his two sons had attended. Eight years later, he co-founded the First National Bank of John's Creek in Alpharetta, Georgia, and later served as its director. Bennett also contributed to Falcons radio shows.
While still handling his bowl game duties, Bennett is mostly retired, spending much of his free time golfing and hunting.