Dallas Roberts moves from stage to screen in 'A Home at the End of the World'

For several years, says the actor Dallas Roberts, he felt like an outsider in the movie world. He couldn't get auditions, he didn't seem to know the right people, and, he says, "I spent whole years viewing the film community as my enemy."

Then came "Nocturne." Roberts knew the playwright, Adam Rapp, from New York's Juilliard School and was the first actor to read this searing story of a young man who accidentally kills his sister. The play -- and the actor -- opened to critical acclaim in 2000 at the American Repertory Theatre in Cambridge and went on to a successful run at the New York Theatre Workshop, and Roberts found new doors opening for him.

"After `Nocturne,' I got an agent with enough mojo to get me into movie auditions," Roberts says, over Jack Daniels and ginger ale at a Boston hotel. To his delight, one of those auditions was for "A Home at the End of the World," Michael Cunningham's adaptation of a novel he wrote before "The Hours."

Roberts already knew the director, Michael Mayer, and producer, Tom Hulce, from the New York theater world, so "they didn't feel like enemies," he says. And he felt happy to be considered for the part of Jonathan, an introverted, sometimes caustic gay man who stands at one corner of an eccentric triangle.

"I get a lot of scripts to read," Roberts says, a faint tinge of his native Texas edging his soft voice, "and you know when you're in good hands by page 7, usually. And this one, it was page 2."

Roberts got the part. The movie opened here on Friday, and the actor seems genuinely pleased to have a chance to talk about it -- even though it's still a challenge for him to reduce its complex web of relationships and emotions to a pat one-liner.

"I'd be doing other work," he says, "and people would say, `What's the movie about?' And I just couldn't find the two-sentence, pithy, `an asteroid is hurtling toward the earth and I have to save it' description."

There's no asteroid, but there is a subtly rendered story of two childhood friends in Cleveland, Jonathan and Bobby, and the ways their relationship -- complicated, ambiguous, occasionally sexual, and almost never openly discussed -- changes after Bobby follows his friend to New York and falls in love with Jonathan's roommate, Clare, played by Robin Wright Penn. There is also a newly minted star, in the person of Colin Farrell as Bobby, and a tabloid tempest over the decision to cut some footage that showed the star's genitals. Roberts has a practiced line about all that.

"A lot of ink has been spilled over Colin Farrell's private parts," he says. "But people are going to see more in Colin than they ever knew was there."

Roberts is amused by how Farrell's public image has morphed just in the time since this project began.

"I'd say I was going to be in a movie with Colin Farrell," he says, "and my friends would say, `Who? Colin Firth?' And then there were four months between when I booked it and when shooting started. And in those four months he became -- Colin Farrell."

What struck Roberts about the seasoned film actors in the cast, which also includes Sissy Spacek as Jonathan's mother, was that they were "generous and kind enough to soothe the new guy." He'd often feel "flustered," he says, by having to master the rules of a new medium -- worrying about camera focus, standing unnaturally close to create a natural-looking shot -- and Farrell would consistently step over to say, "It's just you and me. It's just acting."

It also helped, Roberts says, that Mayer was moving from stage to film directing for the first time. "It was great having him there," he says. "At least there were two fish out of water. You could look at each other and say, `How are your gills?' "

Still, Roberts found he had to make adjustments. "We'd shoot a scene and I'd go to bed that night, and my theater brain would kick in. I'd wake up and go, `Oh, I know, I've got a good idea for that scene.' And then -- `Oh no, that scene's gone.' "

It was especially difficult, he says, because many of his most emotionally charged scenes were shot in the first week. But he found it helpful to look at each day's schedule, then read the scenes just before and just after the one being shot, "to try to put it in a little context."

"It wasn't a very structured thing," Roberts says, unlike some elaborate schemes he's heard of, where actors pin up a whole script in their trailer and draw lines across the pages, showing the rise and fall of a character's arc. "I have a superstition. . . . I consider it bad luck to mark the script in any way. Directors give me all these notes and it must drive them crazy, seeing me not write a single thing down."

In fact, at least one director reacted to that habit not with frustration but with awe. Marcus Stern, who directed "Nocturne" at the ART and again in New York, remembers giving Roberts "hundreds and hundreds of notes -- `Nocturne' was so complex. I happened to see his script one time, and there was hardly a mark on it. But he would hit every single one the first time. That's very rare."

Roberts knew early on that he wanted to act. "At 7, I thought, `I'm going to be an actor,' but it was just after `astronaut,' so it wasn't a big deal," he says. He acted in school plays in Texas and Florida, "and by junior high I knew."

He moved to New York to study acting at Juilliard and has lived there ever since; he and his girlfriend, the set designer Christine Jones, are expecting their first child in October. As for his career, he's "completely thrilled and psyched" that he'll be playing opposite Sam Shepard in the New York Theatre Workshop production of Caryl Churchill's 2002 play about cloning, "A Number."

That's not to say he won't be doing more work in Hollywood if he has the chance. He has "tiny, tiny parts" in a couple of other movies, and "that work fascinates me," he says. "But theater is a drug I'm not going to give up."

Louise Kennedy can be reached at kennedy@globe.com.