Bob Kane (Batman creator) and Jerry Robinson (artist) have never agreed upon who came up with the idea of The Joker first. Kane says that he came up with the idea when Robinson showed him a Joker playing card, and that his idea for the character was based on the idea of someone who leaves such a card at crime scenes. Although Robinson doesn’t dispute the card story, he says that he came up with the idea entirely himself and provided sketches and a character outline describing the villain’s personality. However, they DO agree upon who was the visual inspiration to the character was: Conrad Veidt, a film actor who appeared in Casablanca and The Man Who Laughs (later the title of a Joker story).
Taking place in England in the year 1690, The Man Who Laughs features Gwynplaine, the son of an English nobleman who has offended King James II. The monarch sentences the nobleman to death in an iron maiden, after calling upon a surgeon, Dr. Hardquannone, to disfigure the boy’s face into a permanent rictus grin. As a title card states, the King condemned him “to laugh forever at his fool of a father.”