Transcript for Ben Affleck on depression, addiction and how sobriety has made him happier
Reporter: Ben Affleck strides into Xavier high school in new York, with his signature energy, he is fast talking, funny, as we head to the gym where the junior varsity basketball team is preparing for a playoff game. I believe in you. You're going to do it. I have a very good feeling about this game. Reporter: Affleck has a new movie coming up called "The way back." About a group of young basketball players who need to believe in themselves and a struggling coach who needs faith, too, that he can overcome addiction and reclaim his life. Which one's me, this one? Reporter: This is you. Okay here we go. Nice to he Sao you again. Nice to see you again, too. You look great. Reporter: I think you were 27 in our first interview. You're now 47. Like I said, you look the same. I'm quite visible, 47, you can see it. Not getting away with anything. Reporter: A Hollywood star ready to talk about the fault lines of addiction in his life. I got sober when I was younger, when I, in 2001. Which I now look at as a sort of a JV version of what really the problem is. I was sober for a couple year, and then I thought, you know, I want to drink like a normal person and have wine at dinner and so on. And you know, I was able to. I was able to for about eight years. Reporter: But he says he learned that sooner or later your vulnerabilities can find you. I started to drink more and more and more, and it was really hard for me to accept that that meant I was an alcoholic. I was like, I can just go back. I was fine before. I just take a break. I need to slow down. I'm okay, know what I mean? This isn't mean. And I started to drink every day. I'd come home from work and I'd start to drink and sit there and drink until I passed out on the couch. Reporter: Those years spent directly under the glare of the spotlight, the spotlight that first landed on him more than 20 years ago. There he was, a new face lighting up Hollywood, Ben Affleck and his childhood buddy Matt Damon wrote a little movie called "Goodwill hunting." They were still two guys from Boston in disbelief. Chris Moore produced the movie! Whoever we forgot, we love you, and thank you so much! Reporter: But it didn't take long for Affleck to become a certified star, on the cover of all those magazines as a super hero in Batman, in armageddon and a Hollywood heartthrob. And in person, so well-read, so mischievous. He does an improve of bill Clinton. He might take you by the hand. Say, well, Diane, you know, you've got the biggest surplus in American history. We created 22 million new jobs, and he feels your pain, a little town called hope. Reporter: "The town" and "Argo" brought him a new dimension in Hollywood. Kept a kind of balance, as he married Jennifer garner, the beloved actress and had three children. But as years went by, there was rockiness in his marriage. Two times in the last three years he went to rehab, always worried that his drinking was affecting the children at the center of his life. I really don't want my children to pay for my sins. Reporter: Or to be afraid for you. Or to be afraid for me, which is one of the hard parts of being the child of an alcoholic. You think what if my dad gets drunk, what if he does something what if he ends up on TMZ. Reporter: Did you watch the TMZ? I did. I did. I saw a little bit. I saw a little bit of it. So yes, I guess I did watch some of it, although not the whole thing. I know what it looks like to be drunk. I don't need to watch anymore of it. Reporter: A relapse, broadcast around the world. And in that moment, reliving a family history, a family in which so many lives were devastated by addiction. He was a little boy whose grandmother took her life amid alcohol and barbiturates. His aunt had an addiction. So did his father. For me, seeing my dad, he was drunk every day, and that was life. As that got worse, that was really, really painful. I always said, that will never be, I'm never going to do that. I wish he had been sober during those formative years, but what he's taught me is how important it is for me to be sober now during these formative years for my kids. Reporter: He says his mother was his rock. And as his family broke apart he vowed never to repeat it. What was the hardest thing to be honest with yourself about? That I was going to, that I never thought I was going to get divorced. I didn't want to get divorced. I really didn't want to be a split family with my children. And it upset me. Because it meant I wasn't who I thought I was. And that was so painful and so disappointing. Reporter: In yourself. In myself. Reporter: And he says a wake-up call about the dad he is determined to be. I took the last half of the year off, and I just got to be dad, drive to school, pick'em up go to the swim meet. That's where the parenting happens. It's in the cracks. In the moments where you just take them back from soccer and they say something profound or they talk about how they're really feeling about something, and it's like, that's where you get to be the parent. That's joy of it. And that's what I don't want to miss. Reporter: He says, with sobriety, he can now understand more about the anxieties and the depression that have haunted him since the age of 26. I get depressed. Anti-depressants are very helpful. I've taken them since I was it 26 years old. Sometimes they won't tell you about some awful side effect and you come back and say why am I 60 pounds heavier? Oh, you put on a little weight, oh, well thanks. Reporter: He has a new appreciation of a healthy day. He likes discipline, routine, starting with the gym in the morning, then work. He has just written a new screenplay with Matt Damon. I'd like to find some sort of sense and meaning and purpose, you know. I was not raised religious. I'm not a the very good Christian, although I go to church with my kids, because it was important to Jennifer, and now I go, too, and I like it quite a bit. Reporter: Do you ever say to yourself, maybe I can, maybe I can go back, we can go back and reset time and have that family in tact again? You know, there are things that I would love to go back and change. I have regrets. I, you know, I made plenty of mistakes. Some big, some small. I wish I could go back in time and change all kinds of things, but I can't. Reporter: But what he can do now is join that new breed of Hollywood leading men showing a different kind of strength for family and sobriety. Brad Pitt, Bradley cooper. I got sober because of this guy. And every day has been happier ever since. Robert Downey. Reporter: Rob And guys like Bradley and, you know, Robert, have been really helpful to me and really supportive. And they're wonderful men. Reporter: And with his new movie sending a message of hope and a reminder, if you need help, you're not alone. One, two, three, win! My favorite scene in this movie, this is a little bit of a spoiler, is where my character loses his job, because it's really about consequences. And you understand how desperate he is to not have to suffer those cops againsts and how painful that can be. Reporter: On the right, the 47-year-old man, looking at the new path ahead. Five years ahead, you want people to say Ben Affleck is? Five years from now, Ben Affleck is sober and happy and sees his kids three and a half days a week and has made three or four movies that are interesting to him. I directed two. That he's hopefully proud of. And is in a healthy, stable, loving, committed relationship. Reporter: Sao he inside of you. I really set myself up for that one. Got to make it now. Our thanks to Diane.
This transcript has been automatically generated and may not be 100% accurate.