Johnson relinquished the lead when he and crew chief Chad Knaus decided to change all four ties on his No. 48 Chevrolet during the last round of pit stops. He drove around eventual runner-up Tony Stewart with two laps to go and held it for his second victory this season, the 42nd of his NASCAR career.
"To have to run that hard to pass that many good cars, that's a challenge," Johnson said after becoming the seventh active driver with multiple wins at the "Monster Mile" at the Dover International Speedway. "I had to really suck it up and get going. We've been fast, but this was a very special car today."
Johnson led the race a career-high 298 laps.
Greg Biffle, Matt Kenseth and Kurt Busch completed the top five finishers.