Mark Wahlberg on Why Making 'The Fighter' Became an Obsession

The actor says he trained for four years, eight to 10 hours a day, not knowing whether the film would even get made.

Mark Wahlberg, who plays blue-collar boxer "Irish" Micky Ward in the upcoming film The Fighter, told CBS' 60 Minutes that making the movie was far from easy.

For four years, the actor underwent a grueling training schedule -- building a boxing ring in his own home and training eight to 10 hours a day -- not knowing whether the film would even get made as directors and co-stars came and went.

"There were certainly times where I would wake up at 4:30 in the morning, you know, my trainer would ring the bell, and, 'Oh God,' " said Wahlberg, who insisted on doing his own stunts. "I'm like, 'I better get this movie made.' You know, 'Kill somebody if I don't get this movie made.'" [EXCLUSIVE VIDEO: Wahlberg talks to THR about training for The Fighter.]

But Wahlberg persisted because he could see glimpses of his life story in Ward's; both are one of nine kids and grew up in working-class Massachusetts. He also was a huge fan of Ward's, calling him a "local sports hero."

Meanwhile, doing his own stunts in the movie resulted in him nearly getting his nose broken a couple of times.

Because when we shot the fights, the goal for me was always to make it as real as possible," he said in the 60 Minutes episode that aired Sunday. [Watch video of the interview here.]

The actor, who grew up in the Dorchester section of Boston, dropped out of school when he was 13 and used to sneak out of his bedroom window at night to drink and steal things including cars.

At age 17, he was sentenced to prison after attacking a man with a stick over two cases of beer; the man lost an eye.

"At first, I'm thinking, well, I'm one of the guys now. I made it. And then I just realized, well, this is what it means to be one of the guys. And I just wanted more out of my life," said Wahlberg, who served 45 days behind bars and says a lot of his childhood friends are "either dead or in jail."

After leaving prison, he turned hislife around, becoming a rapper and modeling for Calvin Klein in his underwear.

But Wahlberg nearly didn't pursue an acting career; he credits Penny Marshall with pushing him into acting. She called him while she casting her movie Renaissance Man.

"And when I sat down with her, I was like, 'Nah, I don't wanna act.' She goes, 'What do you mean? You're acting all the time, you're acting right now. You know, you're just acting like you're cool, you act like a tough guy. You know, take the pages. Go outside, look 'em over, and then come back in, and, and audition for one of the parts,'" Wahlberg said.

He ended up getting the job and went on to an acting career that has included starring roles in blockbuster movies as well an Oscar nom for The Departed. Wahlberg also has become a successful producer, with credits including HBO's Entourage and Boardwalk Empire.

Wahlberg says his biggest regret is not finishing high school.

"Imagine what I could have done with a real education; I'd be running whatever studio I work for now," Wahlberg said.

But he still realizes how fortunate he's been. Asked how he defines himself, the actor replied: "A lucky son of a bitch."