Rager's connection to racing began almost from infancy. At age four he drove a "space ship" go-kart around a track during an intermission at his father Bob's race program at the Nebraska State Fair in Lincoln. At fourteen he bought a stock car for $35 and began racing at a local track. His first sprint car victory came at Jefferson County Speedway in Nebraska, the starting point of a career that would span multiple decades and disciplines.
Rager built his reputation as a sprint car racer through the late 1960s and early 1970s, winning races all over the country. In 1973 he was named captain of the United States sprint car team that competed in South Africa, a mark of his standing in the sport. He also set a world record for the fastest lap on a one-mile dirt track, piloting a wingless sprint car.
His most enduring achievement in sprint cars was his dominance at Knoxville Raceway in Iowa, where he became the only driver to win feature races in the 1960s, 1970s, 1980s, 1990s, and 2000s — spanning five consecutive decades of competition. He won the track points championship there and was inducted into the Knoxville Hall of Fame in 1990.
After a period away from sprint cars following his IndyCar years, Rager returned to the discipline when he was in his late forties. Starting again with what he intended to be a single-event comeback, he finished second in both the heat race and feature, and elected to continue. Over the following decade he won an additional 30 features, including four at Knoxville Raceway, one of which was a national qualifier in the 360 class. He also claimed the Masters Championship at Knoxville three times in six years.
Rager began running USAC events in 1976 and made his first Indianapolis 500 qualifying attempt in 1977, ending that run in a crash at 190 mph. He narrowly missed the field in 1979, qualifying last among the alternates. In 1980 he qualified with the tenth fastest time and started the race from the fourth row alongside A.J. Foyt. In the early laps of the 1980 Indianapolis 500, Rager was not merely keeping pace with Foyt but actually ahead of him — leading Foyt and briefly the entire field for two laps before the race settled into its longer narrative.
Rager finished his IndyCar career with six top-ten finishes in 23 starts across USAC and CART events and was named USAC Rookie of the Year for 1980.
In 1988 Rager purchased a resort on Loon Lake just west of Pequot Lakes, Minnesota, where he built Rager's Acres Seasonal RV Park. The resort became the focus of much of his time through his later years. He retired from racing after being inducted into the National Sprint Car Hall of Fame on May 29, 2009.
On June 22, 2011, Rager was inducted into the Big Car Racing Association (BCRA) Hall of Fame. He died on February 16, 2022, at the age of 73.
Among his honors: USAC Rookie of the Year (1980), USAC "Action Track" Driver of the Year, sprint car team captain for the USA in South Africa (1973), track championships at Knoxville and Minneapolis (North Star Speedway), Washington State Championship, NSS National Champion in 2000 and 2001, Knoxville Hall of Fame, National Sprint Car Hall of Fame, and BCRA Hall of Fame.
Roger Rager's career is remarkable for its breadth and longevity. Few drivers in American open-wheel history have competed at world-record pace in sprint cars, led the Indianapolis 500, and then returned to win features at the elite level years after most careers would have concluded. His five-decade winning record at Knoxville Raceway alone sets him apart as one of the most durable performers the dirt-track world has produced.