The actor, 48, who previously told reporters he had an injured ACL (a ligament in the knee that connects the femur with the tibia), tells PEOPLE he's doing just fine.
"It wasn't life or death," Pitt, who slipped down a hill while carrying 3-year-old daughter Vivienne, said at Monday's New York Film Critics Circle Awards. "It was just an old man tripping."
He said he doesn't expect a prolonged recovery, and he was able to walk the red carpet and use the stairs with minor use of his cane. It's "not too bad," said Pitt, who took home the best-actor award for his work in Moneyball and Tree of Life.
"I know how hard he works," Jolie, 36, said of her partner's honors. "And I'm very proud of him."