Joaquin Phoenix won best actor for playing a failing clown who finds fame through violence in the dark comic-book tale "Joker."
Phoenix, a strict vegan, gave a long, impassioned acceptance speech about climate change and animal rights but concluded on a personal note.
"I've been a scoundrel in my life. I've been selfish, cruel at times and hard to work with, and I'm grateful that so many people in this room have given me a second chance," he said.