Billy Bob Thornton: He plays a cruel PE teacher in his new film – but he has a heart of gold in real life

Billy Bob Thornton is without a doubt enjoying his current Hollywood ad campaign. As sadistic PE teacher Mr Woodcock in his new comedy of the same name, he makes life intolerable for his school charges not blessed with natural sporting prowess. The posters show Thornton, blowing a whistle and in vintage tracksuit, holding a pair of basketballs in front of his crotch area.

Thornton does indeed have balls, or "cojones", as he might say, having adopted the heavily Latino state of Texas as his own, though he was born in Arkansas. And those cojones have allowed this unlikely 52-year-old all-rounder to reach an enviably lofty perch where he has his pick of age-appropriate film roles, makes his own solo albums at leisure. He even snared Angelina Jolie as his fifth – and, he swears, last – wife for a couple of years.

These days, Thornton divides his time between a main Beverly Hills home and a Malibu beach pad, probably a concession to his girlfriend, Connie Angland, and his kids, Thornton being more of an up-all-night-in-the-studio than surfer guy. When he drawls: "Yeah, I feel pretty fortunate at how things turned out," he is clearly not kidding: his earliest days in Los Angeles saw his becoming so malnourished that he was admitted to hospital with a heart condition.

"Making a movie to me is a joy and making records is a joy, so I consider myself a really fortunate person to be making a living and putting my kids through school and doing what I love. I get on my knees and thank the big man every day for what I got," he says.

Thornton has been talking for some time now about wanting to make a "full-on kids' movie". Mr Woodcock is not quite that, but closer than the sort of films he has become famous for – 2003's Bad Santa and 2001's Monster's Ball. In fact, his other 2007 release was yet another example of family-ish fare, The Astronaut Farmer, which Thornton viewed as his Field of Dreams. America did not lap up this Thornton as it did Bad Santa's. It will presumably have more fun with Mr Woodcock.

Woodcock is dating a former beauty queen (Susan Sarandon), who happens to be the mother of one of his most traumatised former pupils, now the bestselling author of a self-help book. Naturally, his former charge sets out to pry his mother from the clutches of his former tormentor.

I worry that Thornton might surprise me further in admitting a passion for self-help books. "I never read one. They'll show up every now and then and a girl will try to get you to read one. I always put them aside. Most of them told you stuff you knew already."

He appears to have a passion for playing coaches, this being his third time following Friday Night Lights (2004) and Bad News Bears (2005). "A lot of people have said, do you really like playing coaches? But it just so happened that these scripts came along and they were the best ones at the time."

It cannot be a coincidence that his father, a "crazy little Irishman" who died of lung cancer when Thornton was 18, was a high-school basketball coach. Unsurprisingly, then, Thornton says he was a sports nut as a kid. "Especially baseball. That's what I wanted to do when I grew up. My dream was to be a pitcher for the St Louis Cardinals and I actually had a try-out for the Kansas City Royals. Then I went to high school and played in a band and suddenly got more popular, and with popularity came trouble. And that's never stopped."

Yet it actually does appear to have stopped some time ago for Thornton. "I would love to do the Disney sort of deal. I actually did one years ago, Princess Mononoke but there was more violence in that one than there is in some of my live-action films." He jokes that his children will never see Monster's Ball. "Even when they're 60. I want to leave that in my will that they can never see it."

If Thornton is bothered by the explicitness of his own sexual exploits on film, he is much more bothered by gratuitous violence. "I'm not sure why it's OK for kids to go to movies where people get their heads cut off but they can't hear someone say 'Dammit' or whatever. I'd much rather have my kids curse than hack people to pieces with a machete."

Despite a deserved reputation for strangeness (antiques give him the creeps and he likes orange food), Thornton is at heart a family man who tells me with apparent seriousness that he never leaves home except to shop at Whole Foods and visit famed Hollywood rock'*'roll hotel the Sunset Marquis. "I used to live there, and I hang out with my old friends there once in a while."

Eleven years ago, Thornton became a classic overnight Hollywood star when his film Sling Blade grabbed the hearts of everyone in town. Thornton won an Academy Award for his screenplay and a Best Actor nod. In the last decade he has acquitted himself memorably in a clutch of seriously eclectic roles.

Thornton is much less well-known as a musician, prompting one album reviewer in the US to snipe: "The only thing sadder than a sack of dead kittens is an actor trying to be a rock star." Thornton laughs, taking no apparent offence.

"I was a musician first. Being a popular movie actor has nothing to do with a success in music. It's not some kind of lark. I do it because it's what I love."

For a man the wrong side of 50, Thornton conjures a perceptible twinkle in his eye.And he looks younger than he did five years ago when Jolie filed for divorce, citing the habitual "irreconcilable differences".

"My mother said that she has friends who call her and ask if I've had plastic surgery. And I get her to tell them what I tell everyone: 'I wouldn't dare.' I have a three-year-old daughter now and that makes you feel younger, but I also take better care of myself these days."

Thornton is well aware that "Angelina Jolie's ex-husband" is a tag he'll always wear. It is not one he minds, perhaps because the pair remain close. He will soon star in a film produced by Brad Pitt, Peace Like a River. "He's a friend, too. We've known each other for years."

His own time in the glare of an increasingly prurient media sparked something in Thornton. When he read the book Trapped, about the real-life cave explorer Floyd Collins who in 1925 created the first true American media frenzy, he snapped up the film rights. He is now attached to the project, to star and direct. He does not miss the prying lenses. "I do feel sorry for Angie and Brad and people like that. The only time you hear about me is when I've got a movie coming out and I like it that way."

'Mr Woodcock' opens on 28 September