WHEN left his native Ireland everything was going his way. The theatre director, already enjoying a toasty career in Dublin, had been offered shows at the National and the Donmar in London. His brother was already in the Smoke. Ryanair had just got off the ground, so he could go home for relatively little whenever he wanted. A happy time, then?

“I was so homesick,” he laughs. “When you decide to live in London as opposed to visit it, and you decide to leave Ireland as opposed to leave for a week, you’ve made a step, you can’t go back.” The emigrant’s lot, as he knows from experience, can be one of fresh starts and new discoveries, but it can also be one of grief, loss and discombobulation.

Little wonder, then, that Cork-born Crowley was determined to be the director who brought Colm Toibin’s beloved novel Brooklyn to the screen. The modern Irish classic tells the story of Eilis Lacey, a young woman who leaves the Ireland of the Fifties for Brooklyn.

“In the Fifties the biggest export from Ireland was young people,” says Crowley when we meet before the London Film Festival premiere of Brooklyn, “and the biggest influx of cash was from those young people, from England and America back to the country.”

It suited the government for so many youngsters to leave because it kept the unemployment figures down, says Crowley. For these youngsters, though, it could be a long, tough haul to become established in a new country so far away. Yet the last option for many was to go home.

“The question is why don’t they go back. It’s not just that there is nothing back in Ireland for them, it’s also it’s the shame of the fact that they are not the ones who made it. The myth in the Irish context of going away, making it, and coming home as a successful Yank with the big glasses and the brash clothes is still incredibly potent, and it is sort of not the reality.”

In the film, out next week, Eilis is played by Saoirse Ronan, who was born in New York but came to Ireland when she was a toddler, and the screenplay is by Nick Hornby. The film is a mixture of classical and modern, both true to the book and adventurous cinematically, with jump cutting, hand-held camera work, and a rich, inventive use of colour.

Ronan is perfectly cast, not just because her age, 21, suits Eilis, but because the star of Atonement, The Grand Budapest Hotel, and Hanna, has a face made for close ups, and Crowley loves his close ups. “For me this was a film all about faces … The close up is for me the great thing about cinema.” He quotes David Thomson, the doyenne of film writers, who wrote that "the most special effect in movies is always the human face when its mind is being changed".

This is said with an intensity befitting a theatre director who came to film and television later in his career. Crowley worked in theatre in Dublin, London, and Broadway, picking up awards as he went. He gained a reputation for getting the best out of movie actors who wanted to try their skills on the stage. The list of big screen stars he has directed includes Daniel Craig, Woody Harrelson, Christopher Walken, and Sam Rockwell. He still works on the stage, recently with Cate Blanchett in Chekhov’s The Present, but he is also making his mark on the big screen (Boy A, Closed Circuit) and the small (two episodes of the second series of True Detective).

I ask him for an eejit’s guide to the differences between directing actors on stage and screen.

“With the theatre it is more athletic in the sense that you have to be heard at the back row and you don’t in film. Film is so much more behavioural, which is why you can get amazing performances from non-actors in film, but if you put them on a stage they would die a death. It just wouldn’t work. That idea of presence on a stage is a mysterious thing, how somebody can make you feel like you are sitting right next to them. That’s stage technique allied to talent.”

The way the two forms are rehearsed is also different. You would never, he says, “crack open the emotion” while rehearsing a scene for film because you want that moment to happen on camera. “Once you’ve got it you’ve got it forever.” When you crack a scene in rehearsal it is “written in the wind”. Then, the job becomes working out how to make the same thing happen authentically eight times a week.

He is known for having an ease with actors, a quality he ascribes to one thing: “I’m not scared of them.” He has been asked by other stage directors how to work with film actors, how to manipulate them. “You don’t is the answer. You sit down and you talk and you figure it out. There isn’t a power game at play. I have no desire to be guru with actors, I’ve no desire to be right actually, very happy saying my mistake, I got that wrong.”

There speaks a director who knows what it is like to be far from home.

Brooklyn opens on November 6