While chatting with the CBS late-night host, Affleck addressed his own bad behavior -- groping then-MTV correspondent Hilarie Burton on "TRL" in 2001 -- as well as the onslaught of allegations against his old boss Harvey Weinstein, who produced a lot Affleck's early films for Miramax.
"I don't remember it, but I absolutely apologized for it," Affleck told Colbert of the Burton incident. The apology he's referring to is this tweet: "I acted inappropriately toward Ms. Burton and I sincerely apologize."
"I certainly don't think she's lying or making it up," he continued in his conversation with Colbert. "It's just the kind of thing that we have to as men, I think, as we become more aware of this, be really, really mindful of our behavior and hold ourselves accountable and say, 'If I was ever part of the problem, I want to change. I want to be part of the solution,' and to not shy away from these uncomfortable or awkward or strange encounters that we might've had where we were sort of navigating and not knowing."
On Weinstein, Affleck said: "It was awful to see the extent of these terrible crimes and it was hideous. I haven't worked for Harvey in more than 15 years, but nonetheless, I felt this attachment. I did movies like 'Good Will Hunting,' 'Shakespeare in Love' and 'Chasing Amy' - early movies that I really loved doing, when I still was totally brand new. And so it sort of rained that a little bit to realize while we were having these experiences and making these movies, there were people who ere suffering and dealing with awful experiences. I didn't really know what to do with that, you know? It's hard to know."
The actor, who plays Batman in "Justice League," decided to donate his residual money from the Miramax films he made to RAINN (Rape, Abuse & Incest National Network) once he realized how many women were hurt behind the scenes while his career was blooming.
"I think the most important thing to do is to support the voices that are coming forward, believe them, and create a business where more women are empowered and in place so less of this happens and so that there is a way of reporting this stuff that people can feel safe doing it," Affleck added.
When asked about Weinstein on "Today," Affleck said the allegations have opened his eyes to "the terrible extent of this problem here in our country."
"I knew he was sleazy and kind of a bully, but unfortunately that wasn't that uncommon," Affleck said. "I was brand new to Hollywood. I was 24 years old, I never made a movie and didn't know much of anything really. To now look back on it and think gosh some other people were going through something really ugly and disturbing and difficult and terrible and terrifying... the only thing I could think to do is to give my residuals from my Harvey movies to a couple of organizations that I think are making a difference and try to reconcile that."
The actor also addressed the allegation that Rose McGowan told Affleck about her uncomfortable experience with Weinstein and he didn't do anything about it.
"I don't really want to get into other people's individual stories because I feel like those are their stories and they are entitled to tell as much or as little of those as they want," he said. "I believe Rose, I support her, I really like and admire her tenacity and wish her the best."