Yes. In the comics, there are origin stories for the Joker. For instance, some stories show his transformation due to a chemical accident.
Definitely. The Joker's origin in the comics has been explored in different arcs. It usually starts with him having a somewhat normal existence before something goes terribly wrong. It could be a failed career, a broken relationship, or an encounter with dangerous substances. These events lead to his transformation into the Joker, a symbol of chaos in the DC universe.