Guthrie was originally an aerospace engineer and after graduating from the University of Michigan, she worked with Republic Aviation. She began racing in 1963 on the SCCA circuit in a Jaguar XK140 and by 1972, she was racing on a full-time basis. Her sportscar racing career included two class wins in the famed 12 Hours of Sebring endurance race.
In the 1976 World 600, Guthrie finished 15th, becoming the first woman to compete in a NASCAR Winston Cup superspeedway race. Guthrie would go on to compete in four more races that season. The following season, she competed in her first Daytona 500, finishing 12th when her car's engine blew two cylinders with ten laps to go. For the race, though, she still earned the honor of Top Rookie. Overall, Guthrie went on to compete in 33 races in NASCAR over four seasons. Her highest finish, sixth place at Bristol in 1977, is the best finish by a woman in a top-tier NASCAR race, now currently tied with Danica Patrick in 2014.
Guthrie qualified for and competed in the 1977 Indianapolis 500, in a car entered by Rolla Vollstedt, but finished 29th with engine troubles. She would compete in two more Indy 500s, finishing ninth in the 1978 race while driving with a fractured wrist (injured in a charity tennis event two days earlier) she hid from race officials. Overall, she competed in 11 Indy car events with a best finish of fifth. During her unsuccessful bid to qualify for the 1976 race, many of the drivers in the male-dominated sport stated that the reason she did not qualify was mainly due to her gender. These comments angered then three-time champion A. J. Foyt to the point he lent Guthrie a back-up car to conduct a shake-down test. Her top practice lap in Foyt's car would have been adequate to qualify for the field. She was unable to obtain funding through corporate sponsorship, and was forced into retirement.
Nevertheless, Guthrie's place in history was secure. In 1979, the Supersisters trading card set was produced and distributed; one of the cards featured Guthrie's name and picture.[8] Her helmet and race suit can be found in the Smithsonian Institution and Guthrie was one of the first elected to the International Women's Sports Hall of Fame. She was inducted into the International Motorsports Hall of Fame on April 27, 2006. Her 2005 autobiography, Janet Guthrie: A Life at Full Throttle, has received critical praise in such publications as Sports Illustrated.
Guthrie married Warren Levine, an airline pilot, in 1989. He died in 2006.
In 2011, Guthrie signed a petition in support of the right of women in Saudi Arabia to drive. The petition called on Saudi King Abdullah to sponsor a Saudi Women's Grand Prix. The project was the idea of human rights activist David Keyes.
Qualified, an episode of ESPN 30 for 30 covering her racing career, aired on May 28, 2019. In it she is quoted "You can go back to antiquity to find women doing extraordinary things, but their history is forgotten. Or denied to have ever existed. So women keep reinventing the wheel. Women have always done these things, and they always will."
In 2019, Guthrie was inducted into the Automotive Hall of Fame for her achievements in motorsports. She is the 5th woman to be inducted.
