Clooney arrived with his girlfriend, Sarah Larson, who was also injured in Friday's accident in New Jersey.
"I'm dinged up a little bit, but I'm wrapped up," Clooney told The ShowBuzz's Michele Jarchin, showing off his bandaged hand.
He wore a black suit and white shirt with no tie. Larson wore a knee-length black dress and was propped up on crutches. Her left foot was bandaged.
In addition to starring in "Michael Clayton," Clooney was also its executive producer. Overall, he said, he's a pretty laidback boss.
"I'm not a rotten -- no, I'm an easy boss," he said. "I've been bossed around too many times to be a rotten boss."
The film has already generated positive reviews, some even Oscar-worthy praise, but Clooney says he largely ignores the chitchat.
"You win one and it's really exciting and you dance around the room and call your friends and say, 'Hey! Guess what?'" Clooney said. "And about two days later, when it's sitting on the shelf, you realize you have to really like what you do. When you spend 60 percent of your life doing something you should enjoy doing it."
Clooney has been in the New York area to film the Coen brothers' "Burn After Reading," co-starring Brad Pitt, John Malkovich and Frances McDormand.
Pitt also attended the premiere, but bypassed the media on the red carpet.
When asked about how it seemed that he and Pitt coordinate everything, including projects, Clooney joked: "We do. We call each other -- we actually ask what we're wearing. He's wearing an all-white suit tonight."
"Michael Clayton" opens nationwide Oct. 12.