Busch started the season in a hospital bed in Daytona Beach and ended it with a trip to the championship stage in Homestead.
The 30-year-old Busch beat fellow title contenders Kevin Harvick, Jeff Gordon and Martin Truex Jr. to the checkered flag Sunday. Harvick was the defending series champion. Gordon, who is retiring, was the overwhelming sentimental favorite. Truex was the underdog driving for the small team.
Busch bested them all and joined his older brother, Kurt, as a champion. Kurt won the title in 2004.
Busch, who missed the first 11 races because of a broken right leg and left foot, edged Brad Keselowski on the final restart with seven laps to go in the 400-mile race at Homestead-Miami Speedway.
Harvick finished second, with Gordon sixth and Truex 12th.