Eamon Dunphy has revealed how he "lost it" on 24-hour drink and drug binges during a mid-life crisis.
The outspoken football pundit also talked about the heartbreak of losing his parents and opened up for the first time about the break-up of his first marriage.
He dismissed his relationship with Roy Keane, saying he was "never friends with him".
"I thought he was a fantastic player, a fantastic man in many respects but he's a poor manager," Mr Dunphy said.
The broadcaster also spoke about how he "lost the run of himself" when he turned to drink and drugs.
It began when he was working on radio station Today FM's The Last Word.
"I had my mid-life crisis then. The pressure of working in a drivetime radio programme every night, which was essentially a six-day week.
"They were a brilliant young team, we worked like dogs for 28 days, 29 days. And that period in my life, I was a big party animal, which meant too much drink. I was never a big drinker... I'm not a big drinker at all.
"But too much drink and recreational drugs and stuff like that. It was a period when I was doing that stuff."
He added: "It was a period when I kind of lost the run of myself. If I didn't have to work, I could be a serious party animal.
"I'm three years younger than Mick Jagger, I think I always wanted to be Mick Jagger but it's not possible in Dublin.
"I think there was a lot going on in Dublin, it was the height of the Celtic Tiger, there was a vibe around the town."
He said he took "cannabis mostly, cocaine sometimes".
Mr Dunphy joked he was right when he infamously said "you can't get good coke in this town" in 1998.
"That was a joke I cracked, you can't crack good jokes in Dublin either.
"You can't get good cocaine in this town, it's actually true. I know that, I can testify," he laughed.
His arrests for drink driving forced him to get his life together.
"I was caught drunk-driving on three separate occasions over a very short period of time, which was seriously wrong.
"That was the thing that copped me on, I realised then I'd been a bad boy and it wasn't funny anymore."
In a revealing interview, he said one of the reasons he and his first wife Sandra split was that they married too young.
Mr Dunphy (64) separated from Sandra over 25 years ago and, while they are good friends now, he said they experienced severe financial trouble at one time.
"Life was a struggle, it is for everybody between 21 and 40, I think it's murder. You're trying to get your career, you're trying to get your stuff together. We married when we were 21, too young, I think that's the reason."
He said his decision to follow a career in journalism, rather than football, had an effect on his marriage.
"It was tough because I didn't have any stamps, I didn't claim the dole. I was married and I had one child at the time, it was hell -- it was very difficult. We had a mortgage and we had no money," Mr Dunphy said.
He recalled in a TV3 documentary not having enough money to eat one night.
He and Sandra used to keep cash under the bread bin and "we lifted it up and there was nothing there".
"We didn't go hungry, we went and borrowed a few quid but we couldn't go on living like that. It was a test that my wife and I talked through."
Mr Dunphy -- who married long-term partner Jane Gogan last September -- said there was never any moment when his first marriage "collapsed".
"It just fizzled out. She's a wonderful woman and I try to be a good father. We had our children in common and we get on great," he said.
In This Is... Eamon Dunphy on TV3 this Thursday, viewers will see an emotional Eamon also talking about his childhood.
And he broke down when discussing the heartbreak of losing both of his parents.
He lost his only sibling, Kevin, nearly three years ago.