Despite favorable reviews, Paul Newman was widely felt to be miscast as Billy the Kid since at thirty-three he was considerably older than the character. Billy was supposed to be eighteen at the beginning of the film.
The title of this movie promotes a widespread myth disproven in 1986. Two almost identical tintypes of Billy the Kid were taken at the same time in 1880. The original of one tintype disappeared years ago. The second original tintype was preserved for years in the Sam Diedrick family and came to light only in 1986. Since tintypes are reversed images, the picture from the first tintype led to the myth of the left-handed gun. After the second tintype came to light, the reversed image was reversed to show the Kid as he actually posed, with a Winchester carbine in the left hand and his holstered Colt single-action on his right hip. See Robert Utley, Billy the Kid, A Short and Violent Life, University of Nebraska Press, 1989. Statement following page 110 alongside the picture of Billy the Kid.
The movie was a flop at the US box office. It was far more popular in France and Belgium, especially with politically leftwing critics.
Gore Vidal disliked this film adaptation of his earlier television screenplay, The Death of Billy the Kid (1955), for The Philco Television Playhouse (1948), which also starred Paul Newman. Vidal described it as "a film only someone French could like." He was annoyed when director Arthur Penn expressed criticisms of his original script and brought in Leslie Stevens for rewrites. In 1990, the TV movie Billy the Kid (1989) was made, not only as a remake of this film but as a rebuttal of it, written and largely controlled by Vidal himself. He declared himself pleased with it, but the 1958 film remains better known.