Harvick became the 15th winner of the season on Sunday after leading the last 38 laps following the race's final restart. He took the lead by staying off pit road during the race's last caution and drove away from the field once the race went green again.
The win snapped a 65-race winless streak for Harvick, who last won at Bristol in September 2020.
"We've had several good runs the last few weeks. Our guys have done a good job of taking what we have and maximizing it," said Harvick. "Everybody who doubted us [winning before the playoffs] doesn't know us."
Harvick's win came on a day when several drivers set up for victory were shuffled out of the lead.
Bubba Wallace led the opening 22 laps after earning his first career pole. He was pushed back after a competition caution mixed up pit cycles but ran around the Top 10 throughout the day.
Wallace lined up next to Harvick on the final restart but was passed by Joey Logano, who prevented him from passing for about 20 laps. Wallace got around and tried to chase down Harvick to no avail and finished 2nd.
Christopher Bell took the lead after the competition caution. He won Stage 1 and later was battling for the lead with about 40 to go before making contact with Ross Chastain and wrecking into the wall. Bell finished 26th.
Chatain and his Trackhouse Racing teammate Daniel Suárez also looked poised to challenge for the win.
Suárez held the lead for about 30 laps near the end of the race with Chastain right on his back bumper. The two went to pit road on Lap 157 as drivers began green flag pitstops. That led to Chastain's contact with Bell and trapped the pair out of contention. Chastain finished 24th and Suárez finished 25th after blowing a tire with under five laps to go.
Those events gave Denny Hamlin the lead and presumably the win considering the No.11 had a lot of speed all day.
However, during Hamlin's final pit stop an extra crew member went over the pit wall to get an uncontrolled tire, prompting a penalty that sent Hamlin to the back of the field. Hamlin rallied back to finish 3rd.
Logano and Ryan Blaney rounded out the Top 5. Ty Gibbs earned his first career Top 10 with a 10th-place finish in his third race substituting for injured Kurt Busch.
Another notable incident came on a Lap 25 restart when J.J. Yeley checked up and caused a nine-car pileup. The crash took out Kyle Busch, Austin Cindric, and Aric Almirola, among others. Leading cars were mixed with drivers usually at the back of the pack following a competition caution.
Harvick came into Michigan on the outside looking in at the playoff picture. He now sits in a position to be in the playoffs and would start in a tie for 14th if things stay the same.
The win pushes out Martin Truex Jr., who is 19 points behind Ryan Blaney for the final playoff spot with only three races left in the regular season. Blaney, who has earned the second most points this season, is the only driver of the would-be 16 playoff drivers without a win.
Next week, NASCAR heads to the Richmond Raceway for the Federated Auto Parts 400 on Sunday, Aug. 14.