From my recollection it was caused by the incident in the chemical factory in Batman [1989] - his hair and his finger nails [and god knows what else] wound up tinted green and his skin seemed pretty much bleached. I'm not really familiar with Joker 'lore' or back story so that's the version I'm most familiar with...
The Joker in this film appears to just be wearing makeup, aside from some scarring around the face. I'm just wondering if there is an actual 'in universe' reason for it, Or if they simply gave him green hair to tie in with what audiences are familiar with. THAT is my point. Although I guess doing it cuz he likes it that way is certainly fine plot wise.
And total side note but I always pegged him as an 'expensive shoes' kinda guy. What the hell is he wearing on his feet?
