We have perhaps become a little blase about Brendan Gleeson. Over two decades, the broad-faced, endlessly gregarious Dubliner has carved out a position as one of the world's most admired character actors. You never know where he will pop up next. He could be chewing lesser actors into mulch as Menelaus in Troy. He could be mugging deliciously as Mad-Eye Moody in the Harry Potter series. Despite looking markedly unlike Tom Cruise, his co-star in Mission: Impossible 2, he hasn't been short of leading roles.

He has given us versions of Winston Churchill and Martin Cahill. A few years back, playing the titular cop, he helped The Guard become a domestic smash.

What possible challenges could remain unexplored?

Well, he has never played a duck – thus far. This will change with his appearance as Neil Patrick Harris's stepfather – briefly transformed into that bird – in the efficiently named The Smurfs 2.

Is there a trick to inhabiting a mallard?

“You don’t get into a flap about it. Hey hey!” he says with a flourish.

“No. Not really. Actually, I did turn up when they were ‘shooting’ the duck. But I was in the way. I was giving him directions. He never quite trusted me.”

You may laugh. But the first Smurfs movie made more than half a billion dollars in 2011. It's a safe bet that, come the end of this year, only Gleeson's Potter films will, among the busy actor's credits, have taken more money than the family sequel.

“I wasn’t really aware of the Smurfs,” he says. “I had to do some serious research. It is a bit nerve-racking – putting yourself out on the line like that. I was more worried that I had to galumph about the place and fall over. It’s a bit of pantomime. But I was very happy with it.”

Gleeson did not leap fully formed into offbeat stardom. He has always loved the theatre but he used to earn his living as a teacher even as he plugged away at amateur and semi-professional roles. He wrote his own plays. He became a stalwart of Paul Mercier’s Passion Machine company.

Yet Gleeson has always said that he took his day job very seriously. Unlike other actors who may have waited tables, he seems genuinely to have laboured at two distinct vocations.

“There’s no point in looking back and wishing things were different,” he muses. “There were a few parts I wouldn’t have minded having a go at when I was younger. I don’t regret a second of it. But I did learn what it was to work a normal life. That does help in grounding some of the work.

“I worry about younger actors who haven’t done anything else. They may be talented and good at accessing emotion. But their life experiences tend to be limited. And they often tend towards the spectacular in rectifying that.”

He cackles in his amiable, tolerant way. “They all want to go and jump off a cliff in Brazil. That would ‘broaden their minds’, apparently. At the same time they don’t know what is down the road from them. They don’t know what it is like to work in a shop.”

But what of the second generation of Gleesons? Domhnall and Brian, two of his four sons, are currently making waves in the profession. Domhnall ( 30) has already appeared in True Grit, Anna Karenina, Never Let Me Go and a brace of Harry Potter pictures.

“I have become less judgmental about that since my own lads have come along and they have gone straight into acting,” he says. “But they are aware of other things. They have had other lives.”

Gleeson didn’t become a professional actor until he was in his mid-30s. His wife Mary offered to go back to work. But it didn’t take too long before Gleeson established his reputation as a charismatic, flexible master of the art.

Few other actors can pull off that delicious combination of physical bulk and vocal sweetness. He brings poignancy to monsters and a hint of danger to kindly retainers.

The big breakthrough
By the mid-1990s, following appearances in Braveheart and The General, he was being sought out by casting agents. A trip to Los Angeles was inevitable.

"You do have to go over there," he says. "But it's best to go over with work. I went over with Braveheart and then I went over with The General. It's very important not to be needy in LA. There is so much neediness over there.

“I went feeling ‘take it or leave it’. Whatever happened was grand. I had no particular ambition in that direction at all. The ambition was to work with the people who work there. Because they can bring in the best people. Sometimes you don’t choose well and there’s nothing to be done about that.”

By the end of the century, Gleeson had become close to ubiquitous in Irish cinema. In 1997, he appeared in at least seven domestic features, including Neil Jordan's The Butcher Boy and Paddy Breathnach's I Went Down. John Boorman's The General, in which he played hoodlum Martin Cahill, followed a year later and Hollywood began to perk up. John Woo directed him in Mission: Impossible 2. Steven Spielberg used him in AI Artificial Intelligence.

What is it like working with the auteurs? “I remember making this suggestion to Spielberg,” he says. “I said, ‘Maybe this might work,’ and he said: ‘Well, I see what you are saying but I am just not sure we have time. This balloon has to go there and then it has to go there.’

“You feel they don’t need any suggestions from me. But then you know they are going to raise the bar for you.”

Gleeson may be greatly admired in Hollywood – few profiles fail to wonder when that first Oscar nomination will arrive – but he has become something more significant in Ireland.

When he appeared on The Late Late Show to decry the state of the health service in 2006, few suggested that he was overstepping the mark. He seems to embody the spirit of the nation as we would like it to be: funny, passionate, irreverent and articulate.

A queue of Irish actors
So when he suggested adapting Flann O'Brien's imperishable At Swim-Two- Birds into a film, all Irish actors worth employing seem to have made themselves available, including Michael Fassbender, Cillian Murphy and Colin Farrell, who have all expressed interest.

Although it has been much anticipated, however, the project, which Gleeson will adapt and direct, has never quite made it into production.

“We were very close last year and it just didn’t happen,” he says. “I am trying to not drive it too hard and am just waiting for it to drop into place. If I stress it to death then that is just what will happen. I am hoping I am still ready to do it. I do actually feel calm about it. I feel that when it gets reassembled, I will know what to do with it.”

Oddly, despite the reams of good jokes in At Swim, it might be easier to make a film of Finnegans Wake. For all the affection O'Brien kicks up, he's never made it on to tea towels in the manner of James Joyce. "But I think he is here to stay," says Gleeson. "Anybody who is an aficionado stays with him. Whether he'd want to be on a tea towel I don't know. Ha ha! That I really couldn't say. But I don't think he'll ever be forgotten."

To tide us over, we have John Michael McDonagh's follow-up to The Guard. In Calvary, Gleeson plays a decent priest trying to make sense of a troubled world. Are we looking at some sort of corrective to the clerical scandals?

“Oh no, no I don’t think it’s that,” he says. “It’s about how hard it is to be a good man when you are in a uniform that had been unhealthily looked up to for a long time, then the whole thing was flipped and you’re a pariah.”

And of course there's The Smurfs 2. He's done Churchill. He's done the ancient Greeks. And now he's finally done that duck. "Yes. That one's finally been crossed off the list. I have that now."

The Smurfs 2 is on general release