Racing ran deep in the Reutimann family. David's father Buzzie was a prominent dirt-track competitor, and David began his own career in dirt-track modifieds and late models. In 1997 he moved up to the Slim Jim All Pro Series, earning Rookie of the Year honors with eight top-ten finishes and a fifth-place points result. He followed that with a second-place championship finish in 1998, also collecting the Sportsmanship award.
Reutimann made his Busch Series debut in 2002 at Richmond International Raceway, driving the No. 87 GEICO Chevrolet for NEMCO Motorsports. He showed early promise, leading twelve laps at Memphis Motorsports Park and finishing inside the top-fifteen in subsequent starts. That same year he secured his first three series wins and finished second in the overall championship standings. In 2003, he won a Hills Bros. Coffee promotion that paid for his entry into five Busch Series races, finishing fifth at Nashville and The Milwaukee Mile.
In 2004, Reutimann joined Darrell Waltrip Motorsports in the Craftsman Truck Series, winning the pole in his second race at Atlanta Motor Speedway and earning Rookie of the Year honors. He claimed his first career victory in 2005 at Nashville Superspeedway. He went winless in 2006 but added two poles and finished third in the championship standings, also making fifteen Busch Series starts with four top-tens.
Reutimann moved to the NASCAR Cup Series in 2007 with Michael Waltrip Racing, immediately drawing attention as a Raybestos Rookie of the Year candidate. His debut Daytona 500 was marred from the start — the entire MWR operation was penalized for illegal fuel additives found before the Gatorade Duels, and Reutimann was sent to the rear of the field. He ran well until being collected in an accident on lap 173, finishing 40th.
At Fontana the following week, Reutimann suffered one of NASCAR's hardest crashes in history when Greg Biffle accidentally tapped his bumper, sending him head-on into the outside wall. The car burst into flames and Reutimann was rendered unconscious, requiring helicopter transport to hospital. He sustained a minor concussion, cracked rib, and bruises but returned to competition the following weekend.
The 2009 season delivered the signature moment of Reutimann's Cup career. At the Coca-Cola 600 on May 24, crew chief Rodney Childers made a bold fuel-conservation call on lap 222 that put Reutimann into the lead. Rain then red-flagged the race on lap 227. After a one-hour delay, NASCAR officials declared the conditions would not improve and called the race — giving Reutimann his first Cup win under unusual circumstances. He became the first driver in Cup history to win a race without leading a single lap under green, and the first driver ever to win in the No. 00 in Cup competition. The victory also made him the twentieth driver to have won races in all three of NASCAR's top series (Cup, Nationwide, and Truck). Additionally, the Coca-Cola 600 that year marked the race's fiftieth running at Lowe's Motor Speedway.
In 2010, Reutimann added a second Cup win at the LifeLock.com 400 at Chicagoland Speedway, chasing down Jeff Gordon and pulling away in the final 70 laps to hold off Carl Edwards. His personal-best Daytona 500 result of fifth also came in 2010. Between 2007 and 2011, he recorded two wins, 26 top-tens, and four pole positions in Cup competition.
The 2011 season was disappointing, and Reutimann could not reach a sponsorship agreement with Aaron's for 2012, leading Michael Waltrip Racing to release him. He subsequently drove for Tommy Baldwin Racing sharing rides with Danica Patrick, BK Racing, and other smaller teams through 2013, before making his final Cup appearances in 2014 with Front Row Motorsports.
After stepping away from full-time racing, Reutimann founded Beak Built Chassis to develop UMP modified cars for dirt-track competition. In 2019, he joined Lee Faulk Racing as crew chief for late model driver Ryan Rackley, returning to the grassroots racing world where his family's motorsport story began.