Doc Hudson is the retired Piston Cup champion voiced by Paul Newman in Pixar's Cars.
Doc is a 1951 Hudson Hornet who once raced under the name Hudson Hornet. He won three Piston Cups, including the 1951, 1952, and 1953 seasons, before a serious crash ended his racing career. In Radiator Springs, he serves as the town doctor and judge.
His history explains why he initially reacts harshly to Lightning McQueen's arrogance. Doc recognizes the dangers of treating racing as a single-minded pursuit, because his own career was effectively discarded when newer racers arrived.
The King, also called Strip Weathers, is another Piston Cup champion, but he is voiced by Richard Petty. Chick Hicks is Doc's rival in the first film, not the character played by Newman.