I kind of don't want to know his name. His mysterious backstory, his insanity, which is so interesting and such a deep character to have, I feel it will be strange to put a name to that. Like john, or jack, or any other name it just sounds wrong.
He is the Joker.
Who the hell would it be then? The character has been around since 1940, older than most DC characters. If its someone we already know thats just cheap. They can build a backstory around a new character rather than simply going for the cheap shock value of him simply being an already established character.
It's John.
JOHN CENAAAAAAAAAA
JOHN CENA IS EVERYWHERE IN MEH SCHOOL!
He is the Joker.
"My name is really Mike."
"NO WAY"
Jack !