The victory was Harvick's second of the season and his first at Martinsville. Harvick has 16 victories in the Cup Series.
Earnhardt had muscled past third-place finisher Kyle Busch on Lap 480 and held the lead until Harvick made the winning pass in Turn 2.
Juan Montoya ran fourth, followed by Jeff Gordon, Matt Kenseth and pole-sitter Jamie McMurray. David Ragan and Clint Bowyer were eighth and ninth, respectively. Mark Martin finished 10th in his 800th race in the Cup Series.
"I hate to be the bad guy here, but we're in it to win it," said Harvick, who ended Denny Hamlin's string of three consecutive victories at Martinsville and became the first driver other than Hamlin or Jimmie Johnson to win at the .526-mile short track since Tony Stewart on April 2, 2006.
Harvick's pass accounted for the last of a track-record 31 lead changes, but it was one Harvick knew would be unpopular in some quarters.
