The North Carolina native began racing on the old dirt track in Hickory, building a hobby class car with friends before becoming the team's full-time driver. When Hickory Speedway was paved in 1967 under new promoter Ned Jarrett, Gant adapted quickly to asphalt. Working with car builder and crew chief Kenneth H. Sigmon, Gant won more than 300 races in the NASCAR Sportsman division and claimed three national championships in 1972, 1973, and 1974. He also ran a construction business, selling half of it in 1979 to commit fully to Winston Cup racing.
Gant made his first Cup start in 1973 at Charlotte Motor Speedway, but his first full season came in 1979, when he contested the rookie-of-the-year honours against Dale Earnhardt and Terry Labonte. In 1981 he joined the No. 33 Skoal Bandit team, then owned by Hal Needham and Burt Reynolds. He finished second ten consecutive times before finally winning his first Cup race at Martinsville on April 25, 1982. In 1984, Gant posted fifteen top-five finishes and 23 top-tens to finish second in the championship to eventual title-winner Terry Labonte. The following year he finished third in points, and in 1985 also won the International Race of Champions (IROC) title, deciding the tie with Darrell Waltrip by outrunning him in a photo finish at Michigan International Speedway.
In 1985, Gant also drove the No. 33 at Talladega fitted with the first telemetry data system ever installed on a NASCAR race car; the data was broadcast live during CBS television coverage of the race.
After three winless seasons between 1986 and 1988, Gant broke his drought at Darlington in the spring of 1989, prompting his famous victory lane exclamation: "The Bandit is back."
Gant's most celebrated sustained run came in September 1991, when he won four consecutive Winston Cup races at Darlington, Richmond, Dover, and Martinsville, tying the modern-era record (set in 1972) for consecutive wins. He added two Busch Series victories at Richmond and Dover in the same month, becoming the only driver at that time to lead both series in wins during the same season. His crew chief was Andy Petree. He dominated the next race at North Wilkesboro Speedway before brake failure ended any chance of a fifth straight victory. At 51 years of age during the streak, Gant finished fourth in the championship standings for 1991 and posted five Cup wins, fifteen top-fives, and seventeen top-tens.
He followed that with another fourth-place championship finish in 1992. His last Cup victory came on August 16, 1992, at the Champion Spark Plug 400 at Michigan International Speedway — also the final Cup victory for an Oldsmobile-badged car. Gant announced 1994 would be his final season and closed out his Cup career 25th in the standings.
Gant holds multiple NASCAR records that remain on the books: oldest driver to win a Cup Series race (52 years, 219 days) and oldest driver to collect his first career Cup win (42 years, 105 days). His career total of 18 Cup wins and 21 Busch Series wins — 39 combined — and a runner-up finish in the 1984 championship reflect consistent excellence across more than a decade of top-level competition.
Beyond racing, Gant appeared in the 1983 Burt Reynolds film Stroker Ace and the 1984 film Cannonball Run II. He continues to live on his 300-acre ranch in North Carolina and, by his own admission, considers himself "a good race-car driver but a great carpenter."