The King uses racing number 43 in Pixar's Cars. He is a veteran Piston Cup champion, voiced by real-life racing legend Richard Petty, and his blue car design reflects the famous number associated with Petty's career.
The King is presented as an admired, experienced competitor near the end of his racing career. His calm professionalism contrasts with Chick Hicks's aggressive behavior and Lightning McQueen's early arrogance. In the film's climactic race, The King suffers a serious crash after Chick deliberately causes contact, prompting Lightning to choose sportsmanship over an easy victory.
Number 43 is a notable reference to Richard Petty, who made it one of the most recognizable numbers in American stock-car racing. The connection is reinforced by Petty providing The King's voice, while his wife, Lynda Petty, voices The King's wife in the film.
Lightning McQueen's number 95 is much more widely associated with the franchise, so it is an easy number to confuse with The King's. The King is specifically number 43, while Chick Hicks races with number 86.