It's a Sunday afternoon, the day after the London premiere of his new film Rampart (opening tomorrow in the UAE), and Woody Harrelson is feeling a little fuzzy-headed. "I've stolen from today," he murmurs. To make up for it, he's tucking into a salad and a wheatgrass power shake. "I just should've stopped," he says of last night's festivities. "That's the thing I haven't learnt as well as I could."
Dressed in jeans and a navy chunky-knit sweater, the boyish Harrelson, forever to be known as Woody from the long-running sitcom Cheers, turned 50 last year. "It was a lot easier than I thought," he says. "It's almost like an automobile that's been chugging up hill. Now I'm on the downhill side. It's so much easier. All I've got to do is apply the brakes every once in a while."
If this sounds like he's planning to slow down, he's having none of it. Judging by one of his recent roles – a quirky sports editor for GQ in Friends with Benefits – he's "up for anything", as he puts it. "If it's a cool part, in a cool piece, I'll try whatever. But I don't mind jumping in and saying, let's jump in the ring, let's go a hundred per cent on this deal. Let's go pedal-to-the-metal, let's redline it."
Just take a look at his new film Rampart, a gritty Los Angeles cop drama from a script written by the crime fiction legend James Ellroy. Directing is Oren Moverman, who previously guided Harrelson to the second Oscar nomination of his career, as a conflicted US army captain in 2009's The Messenger. His Rampart role, as the renegade racist cop Dave Brown, is no less fierce, no less intense. And it took its toll.
"I steeped myself in a paranoia that I think was a bit costly," he estimates. "There were friends that I went off on. They'd be kidding about something and I took it the paranoid way. So things like that were happening quite a bit. Several of my friends said: 'I can't wait until you're done with this movie. You're not acting right.' I was short tempered. Ultimately, I think I shook it pretty well. I'm not thinking that way anymore."
The first time Harrelson got this involved was Oliver Stone's Natural Born Killers, his controversial 1994 study of violence and the media. As the psychopathic Mickey Knox, Harrelson took it to the extreme and admitted to bouts of aggressiveness. Then there was his role as a real-life pornographer in The People vs Larry Flynt, for which he received his first Oscar nod.
"Larry Flynt was probably the movie that affected me the most," he says. "It was almost like I never shook it. I never shook that character. I still have Larry in me. I see it in so many ways. It literally changed me as a person." Like how? "I'd never thought I'd go to jail for something. I went to jail for stuff after that." A supporter for the legalisation of hemp and marijuana, Harrelson was arrested in 1996 after symbolically planting four hemp seeds in Kentucky.
If you wonder why such a gentle soul as Harrelson is attracted to films such as Rampart, his Ohio childhood offers some explanation. His father, Charles, was jailed in 1968 for the contract killing of Sam DeGilia, a Texan grain dealer, and was not released until Harrelson was in college. But he was soon in court again, sentenced to two life sentences for allegedly being paid US$300,000 (Dh1.1m) to kill a judge. Harrelson has always stood by his father, who died in 2007, famously stating: "I don't see him as a murderer. I see him as dad."
Harrelson has also been prone to violent outbursts. In 2002, during a stint on the London stage with Kyle MacLachlan in On an Average Day, he was reportedly wrestled to the ground by 14 police officers after a row with a taxi driver over the destruction of a back-seat ashtray. Another story that did the rounds a few years earlier involved a fracas in a London club involving Bill Murray, a fire extinguisher, a poet called Dirt Box and a broken nose.
While Rampart deals with such issues – Harrelson's character is indicted when he is caught on video for beating a suspect – it's more the study of one man's personal disintegration. His bizarre domestic arrangements – living with two sisters, who have both sired him a daughter each – just add to the intrigue. According to Moverman, this element of the story came out of discussions between he and Harrelson, who both have teenage daughters.
He might seem very laid-back, but even Harrelson worries about his trio of girls, Deni (18), Zoe (15) and Makani (five). "I dropped my daughter off at college recently," he says, choking up a little. "That's tough, man. I just worry … she's going out in the world, and she's just this amazing angel, you know? And the world is absurdly tough. But it's a relatively safe thing, in that it's college and she's on a campus. But that was hard. So in that sense I worry … she's outside of my reach."
At least he can still keep his daughters entertained. He followed Rampart with The Hunger Games, the well-received teenage action-adventure adapted from the novel by Suzanne Collins. Looking set to be the next Twilight-like sensation, it stars the Winter's Bone star Jennifer Lawrence in a futuristic story where randomly selected teenagers are forced to fight to the death. A mentor to Lawrence's character Katniss, Harrelson's character Haymitch reappears throughout Collins's three books. "It's a small role, but a good one," the actor notes. "He's a drunken bum – I was doing a little research last night for the sequel." He's joking, of course, but Harrelson is "contractually obliged" to return in the inevitable sequels. "It'll be a really good movie," he enthuses.
Married now for three years to Laura Louie, his ex-assistant and former girlfriend since 1987, Harrelson and his family live "off the grid" in Hawaii - testament to his strong environmental feelings. He says he's "psyched" to be spending time with his wife and kids these days. "Twenty years ago, I had a wanderlust – I loved travelling. Now I just love hanging out with them in Maui. I just love my family." Perhaps those past troubles are finally behind him.