Ricky Bobby (Will Ferrell) is a NASCAR driver that wants to go fast. While working on the pit crew of Dennit Racing driver Terry Cheveaux (Adam McKay), Bobby acts as a replacement driver. In his first race, after starting in last place, due to entering in the middle of the race, Bobby finishes in third place. By achieving his fame and fortune at Dennit Racing, Bobby soars to NASCAR greatness. While racing, he meets his future wife, Carley (Leslie Bibb).

Bobby persuades Dennit Racing to sponsor an additional team car. Bobby arranges to have his best friend, Cal Naughton Jr. (John C. Reilly), on his team. While Bobby and Naughton succeed in competition, French Formula One rival Jean Girard (Sacha Baron Cohen) represents stiff competition. He outperforms them to become Dennit Racing's latest success story.

Desperate to dominate, Bobby exceeds his limitations and crashes at Charlotte Motor Speedway, which included his car rolling and flipping in the air.

While paramedics attempt to take him to the hospital, Bobby runs around on the track. Wearing only his helmet and underwear, Bobby insists he is on fire. During his recovery, Bobby believes he is paralyzed. After deliberately stabbing himself in the leg, he realizes that he is not paralyzed.

Now, Bobby is eager to rejoin the NASCAR circuit. At Rockingham Speedway, before a race, Bobby completed a test drive, but fear caused him to drive exceedingly slow. Bobby is fired from Dennit Racing and his pit crew works for Girard. Jamie McMurray acts as Bobby's replacement for the Wonder Bread car.

Desperate to remain wealthy, Carley divorces Bobby and marries Naughton. After accusing Naughton of ruining his life, Bobby ends their friendship.

Ricky moves in with his mom, Lucy Bobby (Jane Lynch). Bobby's two sons, Walker and Texas Ranger (Houston Tumlin and Grayson Russell), join him as he works pizza delivery. After colliding with a shopping cart, Bobby loses his driver's license and he is reduced to using a bicycle.

While Bobby is not well, his father, Reese (Gary Cole), teaches him to drive with a live cougar in his car. Then, after his father leaves, Bobby talks to his assistant and partner, Susan (Amy Adams), who persuades him to return to NASCAR, since it is in his nature to drive fast. After deciding to take Susan's advice and race at the Talladega 500, Bobby and Susan become love interests. With the Talladega 500 on his mind, Bobby gathers a race car and pit crew.

Before the race, Bobby makes amends with Carley, Girard and Naughton, while uniting with his pit crew chief and close friend, Lucius Washington (Michael Clarke Duncan). Bobby is forced to start in last place, after spare parts were donated to build the engine in Bobby's new race car. At the start of the race, Bobby passes all drivers except Girard. In the closing laps, Naughton using a slingshot technique for Bobby to pass Girard.

Then, the replacement driver of Bobby's Wonder Bread car causes a massive wreck that crashes all drivers excluding Bobby and Girard. On the final lap of the race, Bobby and Girard collide with each other and their race cars roll towards the finish line. Bobby and Girard exit their cars and run towards the finish line. In the background, "We Belong" by Pat Benatar is playing. Bobby wins the race, but he and Girard are disqualified for exiting their cars, so Naughton officially wins the Talladega 500. At the time of the first major crash, Naughton was in third place.

Bobby, Naughton and Bobby's extended family correct their differences after the Talladega 500.