Homestead, FL -- (Sports Network) - Jimmie Johnson, who is aiming to win his unprecedented fourth straight NASCAR Sprint Cup Series championship this weekend, has signed a contract extension with Hendrick Motorsports that will keep him with the organization through the 2015 season.

Lowe's Companies Inc. also signed an agreement with Hendrick to remain as the primary sponsor of Johnson's No.48 team through 2013.

Johnson enters Sunday's season-ending Ford 400 at Homestead Miami Speedway with a comfortable 108-point lead over teammate Mark Martin. If Johnson finishes 25th or better at Homestead, he will clinch the title, regardless of Martin's performance.

"Jimmie is charting new territory in our sport, and that's due to a combination of natural talent and unsurpassed work ethic," Hendrick said. "How he's committed himself is just incredible, and it shows in everything that he does -- not just on the racetrack. There's no question that he's one of the great champions in all of sports, and he's not done yet."

Since his first Cup start with Hendrick in October 2001, Johnson has accumulated 47 victories and 179 top-10 finishes in 290 career starts. Last year, he tied Cale Yarborough for most consecutive Cup titles with three.

"So fortunate to have my team, job, situation at Hendrick Motorsports," Johnson said. "Lowe's has been nothing but amazing to Hendrick Motorsports, to myself. So very excited about the future.

"The only car I've driven in the Cup Series has been a Chevy. It's been a Hendrick Motorsports Chevrolet and a Lowe's Chevrolet. I'm very proud of that stuff. Certainly look forward to the future, what the years may bring."

Johnson and Lowe's previously were signed through the 2010 season. The partnership was launched in 2001 when Hendrick selected Johnson to drive for the new No.48 team.

Chad Knaus has served as Johnson's crew chief since his 2002 Cup rookie season. Knaus' current contract with Hendrick runs through the 2010 season. He is expected to renew his contract with the team.