Unlike the Crips or the Bloods, the Coen brothers gang is not one of those posses that attracts the attention of the Los Angeles Police Department.

Dear no. The Coen boys roll in Hollywood, the sharks and private jets capital of the world. Entry to the gang is restricted and initiation is mysterious but once in, the rewards are huge. How does everlasting coolness sound? Can even the devil better that tune?

John Goodman would say not. "It was like going home again," says the star of Raising Arizona, Barton Fink, The Big Lebowski, O Brother, Where Art Thou? and now Inside Llewyn Davis. After 14 years, Goodman is back with the writer-director brothers in the tale of a folk musician down and almost out in Greenwich Village as the sixties start.

Though they have made close to 20 films to date, Joel and Ethan Coen have kept some constants in cast and crew. Goodman, 61, is one of them. Actors Jeff Bridges, John Turturro, Steve Buscemi and Frances McDormand (Joel's wife) are others, together with Mary Zophres, costume designer. A newish member of the pack is the musician T Bone Burnett who produced the sublime soundtrack for O Brother and does the same, alongside the Coens, for Inside Llewyn Davis.

Even if he had not met the Coens, there have been plenty of other gangs that have wanted Goodman as a member. He has been a hit in sitcoms (Roseanne), in family films (he is the voice of Sulley in Monsters, Inc) and TV drama (Dancing On The Edge, The West Wing). Then there are the films, among them the Oscars-winning The Artist and Argo besides Coyote Ugly and Dirty Deeds.

In the new film, which also stars Oscar Isaac, Carey Mulligan and Justin Timberlake, Goodman plays Roland Turner, a jazz musician enraged at being considered about as with it as the Jazz Age.

The first sight of Turner finds him slumped in the back seat of a car, sleeping like a bear in hibernation. It is hard to separate Goodman from ursine images. Perhaps it is his height and girth (considerably less these days since he started exercising). Or it might be because he was the voice of Baloo in the ill-advised Jungle Book 2. Maybe it is that he was the narrator on the American version of Great Bear Stakeout, a BBC/Discovery Channel documentary about grizzlies (Billy Connolly voiced the British version).

In the Great Bear Stakeout, there is a scene with a mother bear and her cub. Mommie furriest has just purloined a dead seal that was meant to be a male bear's dinner. When he returns she can stand her ground, or make like her baby bear does and skedaddle. Mommie bear, and your interviewer, took the first option. Mr Goodman, you see, is a grand fellow. But he is also a daunting interviewee.

While publicising Argo, he had an encounter with a paper which did not go well. Goodman sighed a lot, said little, and clammed up when probed about his drinking, saying it was not something he wanted to chat about "to sell a f***ing movie". If interviewers gathered around a campfire to trade scary stories, this would be the kind of tale they would tell.

When it comes to the publicity business, then, Mr Goodman is not inclined to dance for anybody. The first sign of this is when I inquire if he imagined a backstory for his enigmatic character in Inside Llewyn Davis. Goodman is a reader, a book always on the go (the day before we meet, I spy him by accident in a hotel, holed up in the corner, book raised to his face like a mask).

"In a general way," he says. "The script was such that it did all my work for me. I'm going to admit to being lazy on this one. I could give you some story about writing a biography but it would be bollocks. I imagined a few things that happened to the guy. I imagined he was at one time probably pretty hot, pretty passionate about what he did, very good, and now he's … degraded."

The last word is stretched out like chewing gum. While Goodman lives in New Orleans, and has the Big Easy drawl to go with it, he was born in St Louis, Missouri. Acting has taken him to both coasts, including in New York. He arrived there in the mid-seventies, 10 years after Llewyn.

Gotham was a mean old town then, he recalls. The city was broke, the streets were filled with rubbish and the alleys reeked of urine. "There was graffiti everywhere, which to me wasn't an artistic statement as much as it was an FU to everyone else."

New York was not as cold to Goodman as it is to Llewyn. "I was very lucky in that I had a friend I was staying with for a while who was forgiving of the rent, and a girlfriend who worked. I started doing commercials, I was fortunate, which saved me from having to do a lot of other work. At the time I didn't realise how lucky I was, I thought I was selling out and I hated myself a lot for it. But that's bulls***." He looks up quickly. "Pardon me."

He was wrong, he realises now, to think of himself as a sell-out. "I was so lucky I didn't even see how lucky I was. I've gone now to a place of great gratitude." Like many a lucky person before him, he has worked his tail off as well. That was the upside of his perfect-ionist nature. The downside was that he was his own toughest critic, and probably still is.

Yet by the time Goodman got to New York, he was already beating the odds. His father, who worked for the post office, died when he was two and his mother, a waitress, brought three children up on her own. He got to university on a football scholarship and ended up studying drama. After theatre, TV and a few films, he arrived with Roseanne, the sitcom that ran from 1988 to 1997. Goodman played Dan Conner, husband to the titular star and dad to three. The Conners were working class and proud of it.

"It was an antidote to a lot of shows that were on, like Dallas and Dynasty, rich people, escapist stuff. Here we were, two fat people with whiny, annoying kids, trying to make a go of it." America loved it - one episode drew 44 million viewers - and when Channel 4 bought it, Britain adored it too. Goodman's admiration for Barr remains to this day. "She was all the driving force. She was an unstoppable freight train."

His Roseanne years were also his first Coen years, starting with Raising Arizona. It was Barton Fink, though, in which Goodman played an insurance salesman with a sinister side, that revealed not only why the Coens chose him in the first place, but why they kept doing so. Like the films, Goodman's performances had layers upon layers, and his ability to slink from one emotion to another, from affable to menacing, naive to knowing, was beguiling.

In the Coens he found filmmakers who, however weird things got on the screen, were basically men at work, there to do a job. That appealed. "They were smart and economic. You could tell they did a great deal with little money, which showed me a lot of imagination. In Raising Arizona if we couldn't [do something] they would invent ways to do things and took great joy in that. It was a pleasure showing up at work every day. It wasn't like work. It was like, 'Oh boy, I get to go back and hang with these guys.'"

Post Coens, his career took off again, playing Sulley in Pixar's Monsters, Inc. His daughter, Molly, rumbled him as Sulley from the off, but then she was a cartoons connoisseur. "I raised her on cartoons because I loved them. We'd watch old Warner Brothers cartoons." Around that time, Jeffrey Katzenberg was rebranding Disney with great fairy tales with strong female characters, such as the Little Mermaid, and she was taken with those.

"She's done well for herself," he says of his daughter with pride. "She's working as a production assistant on a sitcom and happy with it. It's hard work, but she's 23 years old so she can take it." Like dad, a grafter then. But as he knows, it can be a tough old business. Does he worry about her? We're straying into bear territory here, but he's fine, the only "tells" for his uneasiness the pauses that punctuate his sentences.

"Yeah … I can't … If I start worrying about her that's all I'd do. I have confidence that she was raised properly, by her mother, her grandmother…" He bursts into laughter. The family moved to New Orleans after Roseanne. "I got tired of showbusiness. I didn't want my daughter growing up in that atmosphere. We moved there because my wife could be near her parents when I was away working."

Married for almost 25 years to Annabeth, one suspects Goodman had a large part in his daughter's upbringing too, although these were also his drinking years. Goodman has been sober for seven years and attends AA meetings regularly. It cannot be easy, I say, to take comfort from the anonymity of AA when you are asked in interviews about drinking.

"My anonymity was broken for me. Two nights after I had gotten out of the treatment centre I was driving to an AA meeting and I heard on the radio that I'd just gotten out of a treatment facility. So I said, well, I'm not going to hide it, I'm not ashamed of it, it's the way I was born. And the major premise of Alcoholics Anonymous is to help other alcoholics stay sober. By not talking about it I think I'd be doing a disservice to them."

Another pause and he goes on. "I did a lot of things I was ashamed of, but the fact that I'm an alcoholic is like being a diabetic, it is just what it is, it's a disease."

Was it a tough road back?

"Not at all. Easiest thing I ever did."

It was life or death?

"Yeah."

That rather clarifies things, I suggest.

"Yeah."

Goodman has been in New Orleans for more than a decade, staying there throughout the great flood.

Even nine years on from Hurricane Katrina, he still finds it shocking the way nature and failures of planning combined to cause the catastrophe.

"New Orleans has a lot of strong people, it's a city that nobody wants to see go away. So far it has rebounded quite well. There is going to be another storm and I hope we've learned a lesson from it."

He is at the stage of his career when he only has to leave home for opportunities too good to pass up. Appearing in Inside Llewyn Davis was one. The Monuments Men, out in February, was another. The true story of the Allied corps sent to hunt Nazi art thieves is directed by George Clooney and stars Clooney, Matt Damon, Goodman and Jean Dujardin, Goodman's co-star in The Artist.

He had no inkling The Artist was going to become such an all-dancing, no-speaking sensation. "I thought it was going to be a charming little piece but I snapped to the fact that Jean is brilliant because he didn't speak a word of English at that time."

Goodman got a huge kick out of revisiting those wild west days of silent movies, when studio bosses were kings. "They were people inventing the form and the packaging of it. Those were exciting times. These were all immigrants trying to prove themselves, and they were tough men."

Nearing the end of his visit to the London Film Festival, home is in his sights. When he's not working he is reading, fishing, exercising. "I'm lagging in my exercise. I get so tired when I come home. If I could break the cycle and get more exercise I'd be better off." He balls his face up, rubs his eyes and starts crying like a cartoon baby. "Waaah!!!!!!" There goes that rolling thunder of a laugh again. "Whinging about work. Nobody wants to hear that!"

I would like to hear a lot more but we are out of time. I didn't tell you the end of the bear story. The clip ends with mother bear, after having a good old go, coming to the conclusion that all things considered it's better to pad off into the sunset, especially when the other bear has behaved with such grace during the tussle. n

Inside Llewyn Davis (15) opens on Friday. The soundtrack from Nonesuch Records is available now. The Monuments Men (tbc) is in cinemas on February 14.