The reigning 500 champion began the opening Budweiser Duel alone on the back row, in 25th place, but needed fewer than 10 laps of the 60-lap race to move into contention.
By the end, Earnhardt was in total command.
The 40-year-old driver held off 24-year-old Joey Logano during a dramatic final lap to win in the Duel and become the first driver to go from last place to first in the Thursday night races.
"We have had a great car all week," Earnhardt said. "I'm so glad to be able to get through the Duel in one piece because I know how good this race car is. We are going to have a fun day on Sunday."
The two-time Daytona 500 winner will start that race in Row 2 behind fellow Hendrick Racing teammates Jeff Gordon and Jimmie Johnson. The latter won the late Budweiser Duel, ahead of Kyle Busch who will line up alongside Earnhardt on Sunday.
But the biggest drama during the second Duel involved Danica Patrick, who qualified for Sunday's 500 despite a another crash involving Denny Hamlin. A five-car mix-up caused by Hamlin during Wednesday's practice session forced Patrick to finish in the top 15 of Thursday's race using a backup car.
With three laps remaining, Patrick sat comfortably in eighth place with Hamlin closing when her No. 10 car suddenly got loose in Turn 3 to cause a multiple-car crash. As she headed to pit row, Patrick told her spotter, "Denny wrecked me again."
Hamlin did not agree and traded impassioned words with Patrick after the race.
Patrick's crew was able to get her back on the track. Starting in 18th place for a green-white-checkered finish, Patrick made up eight spots to finish 10th.
"It felt dire," she said of her situation.
Gordon, who locked up the pole position on Sunday, finished second to Earnhardt during the opening Duel. More important, Gordon — a three-time Daytona 500 winner — emerged from the race with his car intact after he posted a blistering qualifying lap of 201.293 mph.
"It was a dogfight out there," Gordon said.
Temperatures that dipped into the 30s kept away only the most hearty and dedicated fans. But the weather made for favorable driving conditions as tires stuck like glue to the track. The conditions allowed for frequent three-wide racing on the 2.5-mile oval at Daytona International Speedway.
Sunday could be a different story. Clear skies and temperatures in the high 70s are expected, making for a slicker track.
"I don't think the cars will drive as good as they did tonight," Gordon said. "You can't be as aggressive."
Earnhardt led 13 laps during last Saturday's 75-lap Sprint Unlimited. The next day, he had a strong qualifying run, but his car failed inspection to drop him to the back row on Thursday night.
Once he got into contention, Earnhardt stayed there. He took the lead from Matt Kenseth on Lap 44 of 60.
Earnhardt then held on through a final restart with five laps to edge out Gordon and Logano. Tony Stewart finished fourth and Clint Bowyer fifth, despite experiencing two crashes this week.
"That last lap I just had so many damn cars in the mirror I couldn't count 'em," Earnhardt said.
Logano, though, posed the primary challenge to Earnhardt.
But when Logano tried to pass him for the lead on the low side of the track, Earnhardt blocked Logano to hold on for the win.
Many eyes were on the ever-popular Earnhardt a day after the anniversary of his father's death in 2001 on the same track.
Yet the feel-good stories abounded.
There was no bigger surprise than 22-year-old Ty Dillon. The grandson of legendary team owner Richard Childress finished 16th to earn the final transfer spot for Sunday's race.
"It means so much," Dillon said. "It's hard to explain. I've been coming here since I was a kid watching my grandfather's cars race."
Like Dillon, Earnhardt has been a fixture at Daytona since he was a child.
He hopes to become a fixture in Victory Lane, but realizes Thursday is just a start.
"Winning the Daytona 500 is a real challenge," he said. "The challenge didn't get any easier tonight."