Jim McWithey was born Grammer, Indiana. He raced in Midgets and competed AAA sprint cars between 1956 and 1961.
He made his first attempt to race at Indy in 1956 but fialed to qualify the Dayton Steel Foundry Schroeder Offy. He attended 11 races that year, failing to qualify on 6 occasions. He finished twice with a best resukt of 11th on the dirt oval in Phoenix in December.
In 1957 he crashed in qualifying for the Indy 500 and didn't finish a single sprint car race and 1958 was no better.
He finally made the grid at the Brickyard in 1958 and after qualiying his Kurtis 500C Offy in 33rd he crossed the line in 16th place. He then drove a Lesovsky Offy and put together a run of respectable results which saw him finish 4th on three occasions in September and October.
He started 1960 in the Kuzma Offy finishing a career best third at Trenton and followed this with fourth at Langhorne, both in April. In MAy he once again qualified the Epperly Offy at Indy but down in 32nd spot. In the race he lost his brakes and retired. In five more racse that year he failed to qualify or finsih.
1961 saw him fail to qualify in the four races he attended and he retired.
Later he became a car salesman in Anderson, Indiana.