Doc Hudson won three Piston Cups before becoming Radiator Springs' doctor.
In Pixar's Cars, Doc's earlier identity is the Fabulous Hudson Hornet, a champion racer who won the Piston Cup in 1951, 1952, and 1953. A serious crash ended his racing career, and the racing world moved on without celebrating his recovery.
Doc eventually settled in Radiator Springs, where he became the town's doctor and judge. He initially hides his past from Lightning McQueen, partly because he does not want to relive the way racing treated him after his accident.
Doc's history becomes important when he coaches McQueen and recognizes the young racer's potential. The character is based on the real racing reputation of the Hudson Hornet. Strip “The King” Weathers is another Piston Cup champion in the series, but he is not Radiator Springs' doctor.