It is the afternoon after Donald Trump’s election and a virtual pall hangs over Dublin. Brendan Gleeson is circling the sofa before settling in for a characteristically articulate consideration of the actor’s life. He watched a bit of the count. He doesn’t seem all that surprised.

“But I ain’t going to talk about that,” he says firmly, but politely.

That seems wise. All that needs to be said will end up being said.

Gleeson is here to point us towards another scene-stealing supporting performance. In Ben Affleck's Live By Night, a period noir adapted from a Dennis Lehane novel, the great man plays a charismatic, divided police officer. The film is a welcome throwback to the post-war noir that he and I grew up watching.

"They were on telly then," he laughs. "And I can still remember going to the cinema as a kid and there'd be two films on. I remember those B-movies well. But I remember being in the States and somebody telling me that she liked 'old Hollywood movies'. She was talking about Saturday Night Fever. Ha ha ha!"

He cackles heartily like a ginger Father Christmas.

"And this is even 10 or 13 years ago. Saturday Night Fever was 20 years ago at that point. But of course! I remembering wondering if I could ever get to the stage where I'd say '20 years ago'. That seemed like such a long time when you were young."

Twenty years ago, Gleeson was just edging into a new, exciting phase of his life. As everybody knows (or should know) the burly, warmly voiced Dubliner spent many years working as a teacher before becoming a professional actor. He was 34 when he took the plunge. By the late-1990s, having shone in Irish films such as I Went Down and The General, the American roles were starting to trickle in. Sometimes, even in this cruel world, talent will out. He is now among the most respected character actors in the business. Everyone half-assumes he must have a shed-load of Oscar nominations. Outrageously, he has none.

“It never crossed my mind I could be a movie star,” he says. “I remember being asked when I was about three what I wanted to be and I said ‘an actor’. You go through your teens and you realise the world is slightly different to your dreams. I never put that down as something viable. I suppose everyone imagines themselves up on the silver screen at some point. I never worked towards that though. I just liked the work.”

Literary references

A careful reader who drops literary references into his conversation, Gleeson did study acting as a young man, but, sensible as well as gifted, he made sure he had a decent career to fall back on. He still has the open, engaged manner of the teacher you remember with affection. In a parallel universe, I imagine a famous writer, interviewed in his prime, praising “Mr Gleeson” for turning him on to Shelley and Kavanagh. Can he imagine such an existence where, a teacher by day, he plugged away at amateur theatre in his spare time?

“Oh totally,” he says. “I thought that’s what I would have done. If it hadn’t been for Paul Mercier, that is probably what would have happened. He didn’t see barriers at all. He felt he could bring theatre to a large audience. I was then in the Olympia before 1,100 people. Ten weeks a shot. It became oddly normal to be doing that even before I was a professional actor. When I changed over I was interested in film, but it was maybe a year and a half before I got in front of a camera.”

The importance of Paul Mercier's Passion Machine Company cannot be overestimated in the Gleeson story. Throughout the 1980s, Gleeson appeared in a series of energetic, furious theatre pieces that caught the zeitgeist with uncanny accuracy: Brownbread, Home, Wasters. Gleeson wrote plays for the company. He developed an ability to connect with audiences. This was rare theatre that connected with critics and the public. The partnership between Gleeson and Mercier inspired the next generation.

“It was a proper theatrical experience,” he says, now leaning enthusiastically into the conversation. “He understood that. If you give the audience entertainment they will come. He marketed it well. He got theatre into places it didn’t normally go. He understood the importance of not talking to an empty seat.”

Gleeson manages a rare blend of seriousness and self-deprecation. You only have to observe how he occupies the screen to confirm his commitment. But, unlike many peers, he is never too far from a joke. Perhaps it helps that he lived a life outside the business before he achieved fame. Maybe he’s just born that way.

“There’s a certain amount of snobbery that goes on with movie-making,” he says. “It’s only in recent years that comedies have become awards worthy. But if you do proper comedy, you get more human truth than you do from anything. There is a general suspicion: if I was laughing it can’t be that important. There’s this attitude that if you’re glum and you’re introverted you must be a serious actor – as against somebody who has a good laugh. People don’t want to think those people are serious. Ah, well.”

Great character actors

It now seems obvious that Gleeson would slide into the tradition of great character actors that included Lee J Cobb, Karl Malden and (why not?) our own Barry Fitzgerald. Steven Spielberg cast him in AI: Artificial Intelligence. Martin Scorsese used him Gangs of New York. He joined his son, the now ubiquitous Domhnall Gleeson, as part of the Harry Potter team in Harry Potter and the Goblet of Fire. But it takes more than wit and emotional intelligence to succeed on screen. For a big man with a huge presence, Gleeson has the invaluable ability to fall still when the camera requires.

“Every film requires something different,” he muses. “The methodology is different. You have a different amount of input in each film. I just always find it part of the same quest. You are trying to find something truthful and you are trying to expand it into a thing that has universality. You want to share whatever you find truthful.”

Somewhere in the past 25 years or so, that quest brought Gleeson a degree of fame. Thousands once admired him as a stage actor. Millions now revere him as the Irish bloke out of Harry Potter. There are worse things in life. But Gleeson has always seemed like an unstarry sort of fellow. He has been married to the same woman for nearly 35 years. They have four children including Domhnall and fellow actor Brian (who plays the young Brendan in this week's Assassin's Creed).

"The first time it became an issue when I was asked to do Glenroe," he says. "It was tough learning in front of the nation. I remember going into a shop and the eyes burning into the back of my head. I knew that televisual fame is very different to theatre. They really do think they know you. You're part of the family. Browsing became a problem. You go into a shop and then you start to feel paranoid."

He has a bit of cackle and follows it up with a resigned sigh.

“You do feel that you’re all the time being watched. I am uncomfortable with that. But I love this business. And that’s the price.”