In 2004, Busch won the series’ Rookie of the Year title and picked up his first win at Richmond, his first of five wins that season.
Late in 2004, with Terry Labonte retiring, Hendrick Motorsports needed a driver for the No. 5 Chevrolet in the Cup Series. It tapped Busch for the job and in September of 2005, he picked up his first Cup win at California Speedway making him the youngest driver to win a Cup race at the time. At year’s end, Busch was award the series Rookie of the Year.
But Busch’s rise to NASCAR stardom was not limited to one series. He also logged time in the Truck Series for Billy Ballew starting in 2005- picking up wins at Charlotte, Dover and Atlanta. He also ran a limited schedule with Hendrick that same year.
In 2006, Busch qualified for The Chase for the Championship for the first time. In 2007, he won the first race with the Car of Tomorrow at Bristol and went on to win four times that year, but it ended up being a season of change for Busch, who announced his plans to leave Hendrick for Joe Gibbs Racing.
It didn’t take long for Busch to make Gibbs’ decision to hire him pay off – his win at Atlanta Motor Speedway in March 2008 was Toyota’s first Cup win and returned the No. 18 team to Victory Lane.
That year, Busch teamed with Denny Hamlin, Joey Logano and Tony Stewart to capture the Nationwide series Owners Championship for Joe Gibbs Racing for the number 20 car. He ran in the series for three different teams and in 4 different numbers, racking up four poles and 20 top tens in his partial season, 18 of which were top 5's, and of those, 10 were history-tying wins which tied the Nationwide series record for most wins in a season with Sam Ard, who had accomplished the feat some 24 years earlier.
Busch started 2009 in style, winning one of the Gatorade Duels at Daytona and leading the most laps in the Daytona 500 before getting caught up in a wreck.
A week later in California, Busch raced into history, becoming the first person in the history of the sport to win races in two of NASCAR's touring series in the same day by winning the San Bernardino County 200 in the afternoon and the Stater Brothers 300 in the evening. The next week, he won the 2009 Shelby 427 at Las Vegas Motor Speedway in his hometown.
Busch’s 2009 season started with a bang in the Cup Series, but Busch slumped as the season wore on, missing the Chase for the Championship.