Lovers and Madmen

Sticking to the robbery theme, another Joker origin story had him as a bank robber named Jack prior to his transformation. But he wasn’t just any bank robber; he was among the very best. Jack was quite a genius, and always sought a new thrill, so he eventually grew bored and apathetic. Then Batman intervened…Jack got away, but he was more excited than he had been in a long time. That prompted him to leave the Dark Knight a note.

Once he discovered that Batman existed, Jack planned ever bigger robberies to attract the vigilante’s attention. And it worked, but when the two eventually faced off, things didn’t go well for the robber.

One Batarang to the face gave Jack his smile; he felt something for a change. Afterward, a chemical bath (Batman had almost no role in that) completed his transformation. And this was how the Joker was born, according to the Lovers and Madmen storyline.