McGriff's fascination with racing stemmed from an early interest in cars that developed while growing up in Sioux Falls, S.D. He owned a motor scooter when he was about 9 years old and drove farm machinery while working summer jobs before becoming a teenager.
He borrowed his father's Hudson and first raced on September 16, 1945, on the dirt oval at Portland Speedway right after racing resumed in the United States after World War II.
He was the winner of the first Carrera Panamericana in 1950, where he met NASCAR founder Bill France, Sr.. France convinced McGriff to come south and race in NASCAR races at Daytona Beach, the first Southern 500 race at Darlington Raceway. Driving his car cross-country, McGriff raced it to a ninth-place finish and then drove it home to Portland.
France convinced McGriff to race full-time in NASCAR in 1954. He had his four wins that year in the Grand National series. He had 17 Top 10 finishes in 24 events, and finished sixth in the final points standings. McGriff's average finishing position was higher than points champion Lee Petty.
McGriff had two options to choose from for the 1955 season. He was offered a ride in NASCAR to race for millionarie Carl Kiekhaefer's newly formed team. McGriff decided to return home to the West Coast to be closer to his family, and to tend to his growing timber and mill business. Tim Flock drove Kiekhaefer's Chrysler 300 to 18 victories that season and the season championship.
McGriff returned to racing after not racing for around 10 years. He started 41st at Riverside in 1967, and had moved up to second place by the sixth lap. He beat Ron Grable in a photo finish that day.
In 1969, he won the Oregon Auto Racing Championship and in 1970, he won the Oregon Auto Racing Championship again by winning 23 out of 33 races.
In 1971, he reappeared in the NASCAR Winston Cup Series driving the Plymouths of Beryl Jackson and Robert Koehler but was plagued by 2 DNF’s in 3 starts. He continued to race in the Winston Cup Series for a number of years.
He raced at Le Mans in 1976 driving a Dodge Charger. The car ran a 426 cubic inch V8 engine but retired on saturday at 5.05 pm.
He became the oldest driver to win a NASCAR feature race when he won an AutoZone West Series race in 1989 at the age of 61. His 14 wins at the defunct Riverside International Raceway is the most at NASCAR-sanctioned events.
In November of 1996, McGriff made the trip with several NASCAR champions, current Winston Cup, Busch Grand National and Craftsman Truck Series drivers to Japan's Suzuka Raceway for an exhibition race. He started 26th and finished 25th in what was called the NASCAR Suzuka Thunder Special.
In 2002, at the age of 74, McGriff announced his retirement from racing.