Keller raced in the NASCAR Strictly Stock and Grand National series from 1949 to 1956 making 29 career starts. He won two races during the 1954 season and is notable as the only driver in the history of NASCAR's Grand National series to have won a race in a foreign-built car, winning the 1954 road-race at Linden Airport in New Jersey, driving a Jaguar XK120.
In 1954 Keller he also started racing champ cars, racing in the AAA and USAC Championship Car series. he made 32 starts between 1954 and 1959 and also in 1961. He finished in the top ten 13 times, with a best finish of 2nd in 1956 at Atlanta and in 1961 at Milwaukee.
He raced in the Indy 500 five times from 1955 to 1959 and was involved in the crash that took the life of Bill Vukovich Sr. His best finish at the Brickyard was 5th in his last appearance in 1961.
Keller died later that year as a result of injuries sustained in a Champ Car crash at the Arizona State Fairgrounds in Phoenix, Arizona. He was driving the Philipp Offenhauser 'Konstant Hot' in the 100 Mile Bobby Ball Memorial race.