Bill Finger and I created the Joker. Bill was the writer. Jerry Robinson came to me with a playing card of the Joker. That's the way I sum it up. [The Joker] looks like Conrad Veidt — you know, the actor in The Man Who Laughs, [the 1928 movie based on the novel] by Victor Hugo. … Bill Finger had a book with a photograph of Conrad Veidt and showed it to me and said, 'Here's the Joker'. Jerry Robinson had absolutely nothing to do with it. But he'll always say he created it till he dies. He brought in a playing card, which we used for a couple of issues for him [the Joker] to use as his playing card.
Entertainment Weekly writer Frank Lovece official site: Web Exclusives — Bob Kane interview (1994-05-17)