Doc Hudson is the former champion who raced as the Fabulous Hudson Hornet in Pixar's Cars.
Doc is a 1951 Hudson Hornet who lives in Radiator Springs and works as the town's doctor. His racing identity is initially hidden from Lightning McQueen, but old newspaper clippings reveal that he won three Piston Cups and set a record for rookie victories.
His career ended after a crash sidelined him, and he felt ignored when fans and reporters moved on to newer racers. That history explains why Doc is initially hostile toward McQueen's celebrity and racing ambition.
The Fabulous Hudson Hornet name refers to the real Hudson Hornet, a celebrated American automobile associated with stock-car racing in the early 1950s. The King, whose real name is Strip Weathers, is another champion in Cars, but he is not the character with Doc's hidden identity.