In 2006, Harvick decided to run both of NASCAR's Top 2 series full-time.
He won his first Busch Series race of the 2006 season.
He followed the win with a weekend sweep of the Busch Series and Sprint Cup races at Phoenix International Raceway.
Later in the season, Harvick won the Sprint Cup race at Watkins Glen International.

On September 9, 2006, Harvick, only needing to finish 40th or better to clinch a spot in the Chase, did better by slipping by Kyle Busch in turn 4 going into the final lap and holding onto the lead to win the Chevy Rock & Roll 400 at Richmond International Raceway.
This was his third win of the season, and his second "sweep" of the season, having won the Emerson Radio 250 the night before.
This allowed Harvick, along with teammate, Jeff Burton, their first berth, and first for Richard Childress Racing, in the Chase for the Sprint Cup.
On September 17, 2006, starting from the Pole, Harvick won the first race of the Chase at New Hampshire International Speedway, in the Sylvania 300.
He dominated the race and by winning, was able to take the lead in the point standings for the first time in his career.

Harvick would have a substandard Chase run.
He fell to sixth place in the point standings, until he finished third at Texas.
Following that was another dominating performance in the Checker Auto Parts 500 at Phoenix International Raceway on November 12.
Harvick would win that race, moving him up to third in points.
At the season finale at Homestead-Miami Speedway, Harvick would finish fifth in the race and slip to fourth in the final standings to eventual 2006 NASCAR Sprint Cup Series champion Jimmie Johnson.
In the Busch Series, Harvick would be scheduled to run all 35 races, with three different cars (#21, No.
33, #29) and two different teams, Richard Childress Racing and his own team, Kevin Harvick Incorporated.
Harvick had nine wins, 23 Top 5s, and 32 Top 10s.
He clinched the 2006 NASCAR Busch Series championship on October 13, 2006 at Lowe's Motor Speedway in the Dollar General 300.
It was the earliest clinch of the championship ever in the Busch Series, locking up the title with four races to go.
He ended the season with a record 824-point margin in the final standings.
In 2006, Harvick decided to run both of NASCAR's Top 2 series full-time. He won his first Busch Series race of the 2006 season. He followed the win with a weekend sweep of the Busch Series and Sprint Cup races at Phoenix International Raceway. Later in the season, Harvick won the Sprint Cup race at Watkins Glen International.
On September 9, 2006, Harvick, only needing to finish 40th or better to clinch a spot in the Chase, did better by slipping by Kyle Busch in turn 4 going into the final lap and holding onto the lead to win the Chevy Rock & Roll 400 at Richmond International Raceway. This was his third win of the season, and his second "sweep" of the season, having won the Emerson Radio 250 the night before. This allowed Harvick, along with teammate, Jeff Burton, their first berth, and first for Richard Childress Racing, in the Chase for the Sprint Cup. On September 17, 2006, starting from the Pole, Harvick won the first race of the Chase at New Hampshire International Speedway, in the Sylvania 300. He dominated the race and by winning, was able to take the lead in the point standings for the first time in his career.
Harvick would have a substandard Chase run. He fell to sixth place in the point standings, until he finished third at Texas. Following that was another dominating performance in the Checker Auto Parts 500 at Phoenix International Raceway on November 12. Harvick would win that race, moving him up to third in points. At the season finale at Homestead-Miami Speedway, Harvick would finish fifth in the race and slip to fourth in the final standings to eventual 2006 NASCAR Sprint Cup Series champion Jimmie Johnson. In the Busch Series, Harvick would be scheduled to run all 35 races, with three different cars (#21, No. 33, #29) and two different teams, Richard Childress Racing and his own team, Kevin Harvick Incorporated. Harvick had nine wins, 23 Top 5s, and 32 Top 10s. He clinched the 2006 NASCAR Busch Series championship on October 13, 2006 at Lowe's Motor Speedway in the Dollar General 300. It was the earliest clinch of the championship ever in the Busch Series, locking up the title with four races to go. He ended the season with a record 824-point margin in the final standings.
Kevin Harvick