McMurray, driving a Ford, snapped an 86-race winless drought and avoided a multicar crash that forced the race to end under a caution flag.
It was his first victory since July 2008 at Daytona.
The late crash resulted in Mark Martin's car sliding upside down on the track one lap away from the checkered flag. In a separate crash, Ryan Newman's Chevrolet turned upside down, hit the outside wall and then slid down the track and barrel-rolled on the infield grass.
Newman was not injured but he had to be cut out of his car.
Reigning points champion Jimmie Johnson finished eighth but padded his lead to 187 over Martin and 204 ahead of Jeff Gordon.