After 40 years, Eamon Morrissey, who opens in Brian Friel's version of Chekhov's The Bear tonight, still gets a thrill from the uncertainty of theacting business.

In his home in Dalkey there's a portrait of Eamon Morrissey, painted by Edward Maguire, in which the young actor looks about 14 years old. He was, in fact, in his 20s when it was done, but even now, almost four decades on, he still looks younger than his years. The red hair has, it is true, become grizzled, but the face is still as bright, humorous and faintly combative as ever. In the intervening period he has become a complete man of the theatre, an actor who has appeared in countless plays, a director, and the author of half a dozen one-man shows which have brought him all over the world. And all this is on top of appearing in films and being a household name for a dozen years with Hall's Pictorial Weekly on RTÉ.

He is currently in The Bear, part of a double-bill of Chekhov- inspired plays written and adapted by Brian Friel, at the Gate. "Chekhov described The Bear as a vaudeville," says Morrissey. "It's a big knockabout and what he's done - he really is a master - is he's pared it down. It's not just a question of editing it; he's got some kind of elegant richness out of it, and it's a smashing piece.

"The second piece, Afterplay, is a delight. Again it comes from his interest in Chekhov, but it's not ripped-off Chekhov by any means. One of the characters is Sonya, from Uncle Vanya, and it's just about two lonely people who meet in a café bar. It's a delightful human picture and I think it says more about Friel than it does about Chekhov. It's directed by Robin Lefevre, who's grand. No messing, he knows exactly what he wants."

It all began for Eamon Morrissey when he was at school in Synge Street, although there was no theatrical tradition in the family. Feiseanna and stage school were part of his upbringing (encouraged, he now thinks, by his mother, who was a theatre-lover) and, he says, he never thought of being anything else but an actor. Eamon was named after Eamon de Valera, a hero of his father's. He remembers being dragged to old IRA commemorations and being told to stand up straight with his shoulders back when being talked to by the Great Man.

School came to an end before he had done his Leaving Cert, when he was offered a job in stage management and a walk-on part in a production of The Playboy of the Western World, starring Siobhán McKenna and Donal Donnelly. His parents didn't make much objection, but, he says, "it was really leaving the tribe and becoming a bohemian, all the more so because I was an only child". The Playboy took him around Europe and, he says, "I thought this is what life is all about".

"Mind you," he goes on, "I was the worst stage manager in the world and I hated it - but it was a way in to becoming an actor."

After the glamour of the European tour it was back to Dublin and, inevitably, more stage management, combined with the occasional small part. Theatre was poor in those days.

When he was working with Phyllis Ryan and Barry Cassin at the old Eblana Theatre in the Busaras, he was fired as a stage manager and given a part in their next play. Life changed for him there one night. Morrissey had been in the first production of Brian Friel's Philadelphia Here I Come!, playing one of the boys who call on the hero the night before he leaves for America. The play was transferring to Broadway, but only the leads - Donal Donnelly, Paddy Bedford, Eamon Kelly and Máirín O'Sullivan - were being brought out, so he was back doing a revue written by myself when the phone rang. New York was on the line.

I was there that night. I can remember him, white in the gills, going to answer, saying: "I bet they're just looking for Emmet Bergin's phone number." But they weren't. The actor rehearsing his part in the US couldn't cut the mustard and they wanted Morrissey to be, literally, off to Philadelphia in the morning. In those days, when Dún Laoghaire was the furthest Irish plays were likely to travel, it caused a sensation among us. "To get to New York in my 20s was extraordinary," he says. "I'd been to London a couple of times - went to be a star and became a barman, which is the normal course - but we were such a closed-down society then, and even London was nearly as bad. So the openness of a society where you were allowed open your mouth was great. People didn't listen, but you were able to speak your mind before your 40s."

Philadelphia ran on Broadway for a year and then went on a six-month US tour. Morrissey was soon off again, in another Friel play, Lovers, a job which resulted in a further 18 months in the US.

"After that I realised I had to come home," he says. "Because I realised an awful lot of people in America knew more about Ireland than I did. Anyway, I wanted to come back, 'cause of the prevailing wisdom that you've got to express your own place properly to be universal. So home I came and didn't work for a year."

It was at this time that he bought the cottage in Aughavanna in Co Wicklow, which he still owns. "I love it," he says. "I've discovered it's where I'm totally at one, at peace with myself. Usually I'm on my own, though sometimes Ann [his wife] comes down. I go down there and I mightn't see another human being for 10 days and I'm completely happy with it. But I'm aware of the danger. I do become very hermit-like and I find it harder and harder to go back. I can never resolve the conflict between wanting this totally solitary life and the other half of me wanting to be on stage."

He has written six one-man shows for himself, most famously The Brother, adapted from the Myles na gCopaleen column in this paper. There have also been shows about Joyce, Swift, a second Myles show, and one about pub culture called Just the One. The sixth show, Byrne, about an old Wicklow storyteller, has been staged successfully in London and Australia, but never in Ireland. A seventh is proving problematical. "The more I work at it, the more it seems to go away," he says. "But when I get this present show over I'm looking forward to getting a look at it again."

For non-theatregoers he's still probably best known as one of the leads in Hall's Pictorial Weekly back in the 1960s and 1970s, RTÉ's best - some would say only - comedy show until lately.

"It started with Frank Kelly and myself on a show called Newsbeat. It was a magazine programme done for people outside Dublin, a sop to throw them something, what was in the provincial papers. We were literally readers, reading what county councillors or county managers had said, as quoted in the papers. Then we discovered we could put on funny voices, provided we said exactly what they had said. It evolved out of that.

"RTÉ had never done anything like it, and it was such a change for people. You could compare it in a way to The Late Late Show, opening things up to discussion, but on an entirely different level of having a bit of fun. It really wasn't about being awfully clever and satirical, though Frank Hall was writing on two levels. On one level you had this knockabout, over-the-top Ballymagash kind of thing and underneath was this satirical thing, understood by about 3,000 people in the country."

Like many actors Morrissey can have a love-hate relationship with his profession. "Sometimes," he confesses, "I get so sick of theatre, so sick of going in. There's times, too, you seem to rehearse forever. But what is interesting is that I'm still, this week, excited about this thing we're doing, and I wonder what the hell is it, after 40 years, that makes me still full of uncertainty about whether it will work or whether it won't work. It's great to still have that enthusiasm."

Two Plays After opens at the Gate tonight