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.
The No. 29 Richard Childress Racing squad proved it was the strongest team during the regular season in 2010 but ended up finishing third in the overall NASCAR Sprint Cup standings. Now, the team is looking to close the deal in 2011.
Six races into 2011, both Harvick and the No. 29 are at the top of their game once more.
After an engine failure at Daytona International Speedway in the season opener, the team has fought back with a vengeance. Harvick has led laps in five of the six races this season and has posted an average finish of 5.8 in the past five events, including consecutive wins, at Auto Club Speedway and Martinsville Speedway.
That has allowed him to put that Daytona setback behind him and keep focusing on the future.
"Honestly, when we left Daytona, I was laughing because it had been 156 races since we had had an engine problem and it’s hard to get on anybody for one in 156 in this sport," Harvick said. “Our engine guys do a great job at what they do, and, from where I started at RCR to where we are today, I feel like we have the best engine department. I feel like when we started, we were mediocre, mediocre on the engine side.
“It’s one of the best engine departments in the business. There’s no reason to get down on those guys because all I’m going to do is cause more harm than good. Just try to support them, and they figured it out and we’ll move forward.”