Johnson led 94 of 161 laps to become the first driver since 1982 to win the Daytona 500 and Coke Zero 400 in the same year.
There were two different accidents on the final lap, including an 18-car pileup at the finish line.
“That’s tough to do at a plate track,” Johnson said. “A lot of guys were helping me early. I don’t know if I made a bad move tonight. Really proud of that.”
Johnson led the final 32 laps. He was three car lengths ahead of Tony Stewart, who was trying to win the 400-mile for the fifth time.
Kevin Harvick was third, Clint Bowyer was fourth, Michael Waltrip was fifth and Kurt Busch was sixth.
Nobody was sure what style of racing to expect for the 160-lap race. The season-opening Daytona 500 had very little side-by-side racing with cars running in a long single-file line.
The race at Talladega, Ala., the only other speedway the requires the use of a restrictor plate to reduce speeds, seemed to bring back the larger packs of three-wide, 10-deep packs of traffic.
It didn’t take long Saturday to realize despite their similar shapes, Daytona and Talladega now are intensely different.
The long lines were back for the first 350 miles. Things got edgier in the final 50 miles when the lead pack stayed bunched up .
There were a three skirmishes and one big crash in the final 200 miles.
Martin Truex Jr. spun coming through the fourth turn. That collected cars driven by Juan Pablo Montoya, Denny Hamlin and Kyle Busch. Truex was knocked out of the race, while Montoya was sent to the garage for repairs. Hamlin and Busch were able to continue following quick repairs on pit road.
Marcos Ambrose triggered the next accident when he tapped David Stremme in the fourth turn. That crash also involved Greg Biffle, A.J. Allmendinger and Aric Almirola.
The biggest crash came with 11 laps remaining when Hamlin, who had rallied to get back into the top 15, swerved left and right to keep from running into the back of a slower pack of traffic.
His car turned into the outside wall, which sparked a pileup that included Allmendinger, Matt Kenseth, Jeff Gordon, David Reutimann and Dave Blaney. Allmendinger’s car hit Hamlin so hard it lifted it into a pirouette.
Although Allmendinger and Hamlin were slow to climb from their cars, nobody was injured.
The last mishap came with four laps to go when Johnson blocked Ambrose into Kasey Kahne, who hit the backstretch wall head-on.
Throughout all the troubles at mid-pack, Jimmie Johnson stayed out front – and out of trouble.
Five cars crashed in the first turn on the final lap, but NASCAR decided to keep the green flag displayed since none of the cars were disabled on the track. Just as Johnson crossed the finish line, Danica Patrick got turned while running the middle of a huge pack of traffic.
By the time Johnson came around after his cool-down lap, most of the 18 cars involved in the final lap melee were driving the wrong way down pit road to get to the garage.
Bobby Allison was the last driver to sweep the Daytona races in 1982. Fireball Roberts also did it in 1962, while Cale Yarborough did it in 1968 and LeeRoy Yarbrough accomplished it in 1969.