Doc Hudson is a three-time Piston Cup champion before meeting Lightning McQueen in Pixar's Cars. His racing identity was the Fabulous Hudson Hornet, a celebrated competitor whose career ended after a serious crash and a long recovery.
Doc's victories establish that he understands racing at a level McQueen initially fails to recognize. He later becomes Radiator Springs' doctor and judge, keeping his past secret until McQueen discovers newspaper clippings about the Fabulous Hudson Hornet.
The character's biography combines fictional Piston Cup history with the real Hudson Hornet's racing legacy. In NASCAR, Hudson Hornets were associated with the “Fabulous Hudson Hornet” reputation and with drivers such as Herb Thomas. Pixar's Doc is not a literal historical racing driver, but his design and backstory deliberately echo that automobile's real competition history.