Austin is a former starting quarterback himself. Following high school at Brentwood Academy, he went to the University of Mississippi and played quarterback in the early 1980s. He ranks third in passing yards in the Ole Miss records, behind Eli Manning and Romaro Miller. Austin was an Academic All-American in each of his four college seasons and is a member of the University of Mississippi Sports Hall of Fame.
After college, Austin was selected in the 12th round (312th overall) of the 1986 NFL Draft by the St. Louis Cardinals. He played two seasons in the NFL as the team's third-string quarterback, attempting a single pass.
In 1988, the Cardinals chose not to resign Austin, and he instead jumped to the CFL and joined the Roughriders, initially as their back-up quarterback. On November 26, 1989 in Toronto, Austin was at the helm of the Roughriders when they won the 1989 Grey Cup versus the Hamilton Tiger-Cats, winning the MVP trophy for his 474 yards passing in the game. One of the Top 10 quarterbacks in CFL history, with 36,030 career passing yards on 4,700 pass attempts, having completed 2709 passes (57.6%), Austin is a Roughriders legend for leading the team to its second league championship (Grey Cup). He also threw 198 touchdown passes and 191 interceptions in his 10 CFL seasons with 4 teams.
Austin started at quarterback for the Roughriders, British Columbia Lions, and Toronto Argonauts (the second Ole Miss star to play quarterback for Toronto, the first being Eagle Day in 1967), as well as serving as a backup for the Winnipeg Blue Bombers. He is one of only four CFL quarterbacks to pass for more than 6,000 yards in a single season (6,225 in 1992 with Saskatchewan). Austin won his second Grey Cup in 1994 with the British Columbia Lions, starting the 82nd Grey Cup but being replaced at halftime by Danny McManus due to an injury. McManus would lead the Lions to a win on a last-second field goal.
In the Columbo episode A Bird in the Hand... (air date November 22, 1992), footage from a Saskatchewan Roughriders versus Edmonton Eskimos game was used to portray a fictional game played by a football team called "The Stallions". As the footage showed Kent Austin playing and wearing the No. 5 jersey, the actor playing the quarterback wore a jersey bearing that number throughout the television episode. When a scene required seeing the quarterback in play, they used footage of Kent Austin.
In 2003, Austin entered coaching as the quarterbacks coach of the Ottawa Renegades. The following year he was hired as Toronto offensive coordinator, helping lead the team to an offensive surge that allowed the franchise to win the 2004 CFL championship. He was fired in the 2006 season and later hired as Saskatchewan Roughriders head coach for the 2007 season.
On November 25, 2007, Kent Austin coached the Saskatchewan Roughriders to the 95th Grey Cup Championship beating the Winnipeg Blue Bombers 23–19. In doing so, Austin became the first head coach to win a professional football championship for the same team with which he won the championship as a quarterback. He did so in his first year as head coach, and at the same stadium where he won the cup as a player, 18 years earlier. His performance as head coach won him the 2007Annis Stukus Trophy as CFL coach of the year.