Associated Press

Tony Stewart will be an owner-operator for the 2009 Sprint Cup season.

CHARLOTTE, N.C. -- From his seat in the bright orange No. 20, Tony Stewart spent a decade driving his way to superstardom while helping Joe Gibbs Racing become one of NASCAR's top teams.

The partnership produced 32 victories, two Cup championships and more than $68 million in winnings. It also survived a flurry of storms created by one of the most tempestuous drivers in NASCAR history.

It was the perfect union, yet it left Stewart wanting more.

More than he could ever get at Gibbs, where an ownership stake wasn't an option and Stewart was simply the driver. So Stewart secured his release from the organization Wednesday, paving the way for him to purchase his own NASCAR team.

"While this moment is bittersweet, we're parting on good terms and we know that each of us has benefited greatly from the other," team president J.D. Gibbs said in a statement.

The remarkable and often emotional 10-year run will end for "Smoke," "Zippy" and the JGR boys this season.

Gibbs had hoped to sign Stewart to an extension that would keep the 37-year-old driver in his seat past 2009 and until he retired, but Stewart stalled during contract talks. He wanted to see what else was out there, and given the opportunity to buy majority ownership in fledgling Haas-CNC Racing, Stewart couldn't resist. He scheduled a news conference today at Chicagoland Speedway to discuss his latest venture.

Stewart, who owns several sprint car teams and a trio of race tracks -- including Eldora Speedway in Ohio -- will likely model his NASCAR team after the Gibbs organization.

Joe Gibbs has supported "Smoke" unequivocally through a tumultuous 10 years that saw Stewart punch a photographer, engage in run-ins with fellow drivers, fans and the media, and often fall on NASCAR's bad side through his jaw-dropping candor and sharp wit.

He thanked the organization for sticking by him, and teaching him much of what he knows as a businessman.

"I've learned so much from them and have a tremendous amount of respect for what they've built," Stewart said in a statement. "I've modeled my USAC and World of Outlaws teams the same way they built their NASCAR team, and I made it a point to find good people to run those programs."

Now Stewart will have to find the same quality people to help him revamp Haas's two-car team. Current owner Gene Haas began serving a two-year prison sentence for tax evasion in January, and the team is not exactly competitive.

Haas currently fields one car for Scott Riggs, and a second entry that's been piloted by several drivers this season. Neither team is inside the top-35 in points, and the organization was devastated by stiff NASCAR penalties in May for bringing illegal cars to Lowe's Motor Speedway.

But Stewart loves a challenge, and this newest one will also secure him a spot in NASCAR long after he quits driving. He's expected to pilot one of the cars, and fellow Indiana native Ryan Newman is in the running for the second seat. Newman has been noncommittal on his future plans.

Getting to this point, though, meant breaking up a quality partnership.

Stewart joined JGR in a developmental role in 1997 while he was still competing in the IndyCar Series. He ran five races in the Busch Series for JGR that year, and also won the IRL championship. He expanded his Busch schedule in 1998 to 22 events in preparation of his move to full-time Cup racing.

His arrival helped JGR expand to two teams, and Stewart made an immediate impact on the Cup Series.

Stewart finished seventh or higher in the season standings in all but one season -- 2006 when he failed to make the Chase but still won three of the final 10 races and wound up 11th in the standings that season.

Stewart's departure means the end of the longest active driver-crew chief relationship in the garage. Greg Zipadelli helped build the No. 20 team around Stewart at inception, and "Zippy" will likely stay behind at JGR to help groom 18-year-old protege Joey Logano into NASCAR's next superstar.

"No matter what, Tony and I will remain close friends," Zipadelli said. "I know when it comes to the No. 20 team, things will obviously be a lot different next year, but I remain as committed as ever this year to winning races with Tony and securing our spot in the Chase to contend for a third championship."

Although Gibbs officials have not said who will replace Stewart in the No. 20, Logano is expected to fill the seat.