This is supposed to be the year he finally wins a Cup title.
He's married now and has mellowed slightly, showing more maturity on and off the track. He's won four more times to push his career total to 30 and started the Chase as the "top seed."
But Busch has gotten off to a mediocre start through three races coming into Kansas, where his season has gone bust his last few title runs. He's eighth entering Sunday's race in the tightly bunched Chase standings, 15 points off co-leaders Kevin Harvick and Carl Edwards.
"There's 43 guys out here every week that if they don't win, they didn't meet the potential they wanted to," Busch said before qualifying third for Sunday's race.
"There's been times we won races and we didn't feel like we reached everything we needed to reach," Busch said. "It's high pressure, it's high stakes. There's a lot on the line and this is a performance business, and you've certainly got to make the most of it. We're trying every week."
It just hasn't been quite good enough.
The 26-year-old Busch started the Chase with a 26th-place run at Chicago and finished 11th at New Hampshire before a sixth-place run last weekend at Dover restored some confidence.
He had hoped to get off to a better start, knowing Kansas Speedway is rarely kind to him.
Busch came to the 1 1/2-mile tri-oval just 10 points out of the Chase lead in 2007, his final year with Hendrick Motorsports, when he got tangled up with Dale Earnhardt Jr.
Last year, Busch was sitting third in the standings when he spun David Reutimann early in the race. Busch called it unintentional contact, but it didn't sit well with Reutimann. He got payback with 122 laps left when Busch was running seventh, hitting the outside of his car and forcing him into the wall. Busch finished 21st in the race and dropped all the way to seventh in the standings.
In June, a simmering feud between Busch and Richard Childress Racing really ignited.
Busch had bumped into Childress driver Joey Coulter on a cool-down lap after the Trucks race. The 65-year-old Childress showed his displeasure by assaulting Busch, earning a $150,000 fine from NASCAR.
It added another reason for Busch to dislike coming to Kansas.
"When it's one of your least favorite racetracks, it's not beneficial to come here twice," he said. "We'll work hard and take what we can get out of this weekend. We know it's going to be a hard one for us, and we're really going to have to dig in."
Busch got off to a good start with a solid qualifying effort Friday.
He'll roll off alongside Matt Kenseth, who is just ahead of him in seventh in the Chase, with two-time Kansas winner Greg Biffle and Chase co-leader Edwards on the front row.
While Busch would be pleased to leave one of his least-favorite tracks with a decent finish, Edwards will be content with nothing short of a victory.
The native of Columbia, Mo., had a chance to take the solo lead in the Chase last week at Dover, but a pit road speeding penalty cost him an opportunity at a victory. He was furious with himself over the mental mistake, promising to his team over the radio that he would win at Kansas.
It's not such a far-fetched prediction.
Edwards fares well at intermediate tracks like Kansas, and even though he's never won at what he considers his home track, the charismatic driver has three top-5 finishes in nine starts.
"I just told my guys, I was feeling pretty motivated at the end of the race at Dover because of the mistakes I made on pit road," he said. "I told my guys on the radio that we were going to go to Kansas and we were going to win, and let's go do it. That's still my plan."
There's a reason that Busch and Edwards — and a lot of other drivers — are putting a lot of emphasis on Kansas. The driver who left leading the Chase has gone on to hoist the championship trophy at Homestead three of the last four years.
"It feels like we've been running Chase races for a year. The time has really slowed down," Edwards said. "We are only three races in and it feels like a lot has happened.
"I'm looking forward to the last seven races. This race I feel for our team is an opportunity to capitalize on one of our strong points, which is these mile-and-a-half race tracks."
Edwards has already given himself an advantage over Chase co-leader Harvick, who struggled on a windy Friday and qualified 14th in the 43-car field.
Tony Stewart and Kurt Busch are tied for third in the Chase, and both have plenty of ground to make up. Stewart will roll off 23rd and Busch, the winner at Dover, will start 17th.
Denny Hamlin will start seventh, Jeff Gordon 10th, Ryan Newman 11th and Brad Keselowski 12th among Chase contenders. Earnhardt will start 18th and Jimmie Johnson 19th.
"We have two battles right now, one against ourselves and the other against the guy who's second in points," Harvick said. "Don't care where anybody else is."