Chaffin has raced in all three of NASCAR's major series and is currently a free agent. He was a two-time track champion at the historic Nashville Speedway USA, where he met his friend, Andy Kirby.

Chad made his Sprint Cup debut in 2004 at Martinsville. Driving the No. 98 MACH 1 Motorsports Ford, he ran 100 laps before experiencing a mechanical failure and finished in 39th place. In 2005, he attempted three races with Front Row Motorsports and MACH 1. Chaffin qualified for the Checker Auto Parts 500 at Phoenix and finished the race in the 43rd position after overheating issues. He began the 2006 season in the No. 92 Oak Gloves Chevrolet driving for Front Row Motorsports, however, he switched to the No. 34 Oak Gloves Chevrolet within the organization after two races. After another eight races, he yet again moved within FRM, this time to the recently acquired No. 61 team. Chaffin has currently made four of the fourteen races he has attempted, three in the No. 34 Oak Gloves Chevrolet and two cars with No. 61 team.

At the beginning of the 2007 season, Chaffin switched to the No. 37 R&J Racing car but was replaced by John Andretti before qualifying for a race. After Mike Bliss' resignation as the driver of the No. 49 BAM Racing Dodge on June 27, 2007, Chaffin was selected as one of the replacements with Larry Foyt. In his first attempt to qualify of the season at Loudon, Chaffin made the race after Brian Vickers and the No. 83 Team Red Bull Toyota were disqualified after failing post-qualifying inspection. In 2008, he attempted to qualify the No. 34 Chevrolet for Front Row Motorsports in the Pennsylvania 500 at Pocono and the Camping World RV 400 at Dover, but failed to qualify in either.

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