Billy Bob Thornton Wasn't 'Equipped' for Fame in 20s Due to 'History of Certain Chemical Refreshments'

Billy Bob Thornton was in his 40s when Sling Blade (1996) catapulted him to fame with an Oscar nomination for Best Actor and a win for Best Adapted Screenplay. As the actor/writer/director/musician, 66, tells PEOPLE in this week's issue, he's happy to have found success when he did.

"If I had made it as an an actor when I was in my 20s or younger, I may not even be here now," Thornton explains. "I don't think I was equipped in my early 20s to handle that, because I had a history in my late teens, early '20s, of certain chemical refreshments and things like that. I don't know if I would've made it through. I'm happy that things unfolded in a way that I didn't force, that they just happened. I still appreciate that."

Thornton, who hails from Hot Springs, Arkansas, initially moved to Los Angeles to pursue a career in music. A chance encounter would later change the course of his life.

After arriving in L.A., Thornton says he "ended up in this acting class, because a guy I met said, 'You ought to try this. I think you could do it.'"

"The next thing you know, you're starving to death for years and years," he recalls. "People used to say, 'Why didn't you go home, if it was so bad out here?' I said, 'Well, I had nothing to go home to. I was poor there. I'm poor here. What am I going to do?' And then I start getting little parts on something, and it's like, 'Wow, I just made $750 for one day.' I thought, 'Well, maybe I should try this acting.' And then I grew to love it."

One of those parts was a small role in Indecent Proposal (1993) opposite Robert Redford.

Adrian Lyne's thriller starred Redford, 85, as a millionaire who offers a couple, David and Diana (Demi Moore and Woody Harrelson), $1 million for a night with Diana.

Discussing key moments that had a major influence on his life with PEOPLE, Thornton recalls, "I was in scene in a movie that Robert Redford starred in [Indecent Proposal}. During a break, he came up to me and said, 'This is an amazing article.' He was holding a publication with an article praising One False Move [Thornton's 1992 screenplay debut]."

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"He said," Thornton continues, "'This is a great film. You have a career because of this. People are going to sit up and take notice.'

"But then he said, 'Here's what you don't do. Now that you've done this, don't take the next big [film]. Do these kinds of movies and take supporting roles, and then do your own thing before you take a big movie."

"And he was right because a few years later we made Sling Blade," Thornton concludes.

He can currently be seen in The Gray Man, opposite Ryan Gosling and Chris Evans, which is in theaters and arrives on Netflix Friday.