His stock car career took the green flag in 1981 when he won the Mini-Modified division track championship at Kentucky Motor Speedway. In 1982, Michael competed in the Goody's Dash Series. He won the Goody's Dash series title in 1983 and earned the series Most Popular Driver award in 1983 and 1984.

Michael Waltrip's role has evolved since his inception into the Busch Series in 1988. He emerged from a driver, to an owner who currently manages and drives his Busch Series entry. He is running a limited schedule for the 2003 season with his sponsor Aaron's in the No. 99 "Dream Machine."

Michael's most memorable Busch Series race was the 1993 spring race at Bristol. He won the race and made the first ever backwards lap around the track in memory of his fallen competitor, Alan Kulwicki. The memorial Polish victory lap was a tribute to the Winston Cup Series champion who had been killed several days earlier. He also proposed to his wife, Buffy, in victory lane that day.

In 2001 Michael joined a winning partnership. Dale Earnhardt finally said the words one guy had been waiting to hear for quite some time, "I'm glad to announce that Michael Waltrip will be driving for DEI in the NAPA Monte Carlo for the 2001 NASCAR Winston Cup season." Eyebrows raised when 38-year-old Waltrip was picked to pilot the NO. 15 Chevrolet on the Winston cup circuit, but for Waltrip, it was a long time coming.

His first Winston Cup points win came at the 2001 Daytona 500! Prior to that he had won the Winston All-Star race in 1996.

Michael and Dale had been friends and competitors for a long time. Michael even stepped in to drive Earnhardt's Busch Series car a couple of times in the early 1990's. That friendship grew and the idea of teaming together had been brought up more than once since Earnhardt started his DEI Winston Cup program. Timing is everything, and it never seemed to be the right time for the pair. All that changed in September of 2000 when Michael became the newest member of the DEI/NAPA family.