In Pixar's Cars, Lightning McQueen's trainer and friend from Radiator Springs is Doc Hudson.
Doc initially appears to be the town's respected judge and physician, but Lightning learns that he was once a celebrated racer. Doc won three Piston Cup championships and was known as the Hudson Hornet, a reference to the real Hudson Hornet race cars that achieved major success in early stock-car racing.
Doc is voiced by Paul Newman, whose performance was his only voice role in a Pixar feature film. The character's history gives Lightning a lesson in humility: Doc's racing career ended after officials and fans moved on from him following a serious crash.
The film does not present Doc merely as a mechanic. He becomes Lightning's mentor, helping him understand teamwork, responsibility, and the value of Radiator Springs. Doc's story is one of the movie's central links between fictional racing and real motorsport history.