Film: These days the Kid cuts grass in Kentucky

Sam Rockwell is best known as The Kid in `Box of Moonlight', an outcast living in a trailer in the middle of nowhere. Now he stars in `Lawn Dogs' as ... well, an outcast living in a trailer in the middle of nowhere. But, he tells Ryan Gilbey, there the similarity ends.

I have met at least three people who want Sam Rockwell dead. All of them are film critics, a breed known to be gnarled and bitter but not generally given to twisting pins into wax effigies of bright young actors. And what is Rockwell's crime? He simply appeared in the lyrical comedy Box of Moonlight as a wise and wacky drop-out in a Davy Crockett suit who teaches John Turturro's uptight construction supervisor how to savour life.

It took the writer-director Tom DiCillo four years to finance Box of Moonlight, but through all this time he held strong on his choice of Rockwell to play The Kid, despite pressure to cast Johnny Depp or Jason Priestley. Rockwell, for his part, had to keep his hair long while waiting for the film to be made: "If I got a job playing a cop or something, I'd ask Tom if I could cut it," he remembers. "And he'd say, `Yeah, cut your hair, we don't have the money yet - but don't cut it too short because we might get it soon.' Things went on like that for a long time."

Even after the film was finally made, it had a tough time attracting a distributor, and, worst of all, it was rejected outright by the selection committee for the Cannes Film Festival. That it got shown at all is largely down to Janet Maslin, the New York Times film critic, and the first to champion Box of Moonlight after it was screened at the Sundance Film Festival. Maslin singled out Rockwell and quoted the opinion of the Miramax boss Harvey Weinstein: "He's a movie star."

It was a turning point. Previously, Rockwell had done some acclaimed work on television series such as NYPD Blue and Law and Order, as well as fleeting appearances in a few very respectable films - playing with a knuckleduster in Last Exit to Brooklyn and goofing around in a daft hat as Jennifer Beels' tubby brother in In the Soup.

He recalls the first time he was proud of his own acting. "I was in this play, Face Divided, where I played the husband of a woman who abuses our child. I had this scene where I described the kid's face to my wife - we were on the emergency ward and we'd spent the evening denying what had really happened. Then I say `I saw her face, I know you beat her up,' and I describe her face with the wires in it, and as I did it I got very emotional, which was a discovery for me. To be able to do that night after night, to realise that I could consistently craft an acting moment - it was a revelation to me."

Theatre had been Rockwell's passion since he was 10, when he acted in an improvisational comedy alongside his mother, whom he describes as "an American Alison Steadman". Film came later. Rockwell had originally auditioned for the lead in DiCillo's first feature, Johnny Suede, which eventually went to Brad Pitt. When he was offered the chance to play The Kid, he wasn't about to turn it down because of a little hitch like zero finance. He hung in there. "It was a dream role," he says. "They don't come around too often." Perhaps not. But by a strange coincidence Rockwell has chosen to follow his sweet, winning performance as an outcast living in a trailer in the middle of nowhere with Lawn Dogs, in which he gives a sweet, winning performance as an outcast living in a trailer in the middle of nowhere. There is even a scene that is directly reprised from Box of Moonlight, in which Rockwell strips naked to dive into a river.

But despite surface similarities, those who thought that in Box of Moonlight Rockwell was simply doing a junior version of Robin Williams' twinkly man-child routine will be surprised by his depth and poignancy in Lawn Dogs. He plays Trent, a poor uneducated Kentucky handyman who mows the lawns of his affluent neighbours and strikes up a friendship with a young rich girl who feels an affinity with his outsider status. There are whole scenes when Rockwell seems entirely guarded, not only from his fellow actors, but also from the audience. If The Kid was a role which demanded vaudevillian excess, Trent is the opposite, a jamboree bag of secrets, and not all of them are disclosed.

"I really connected with his loneliness," Rockwell recalls. "Low self- esteem and loneliness are the keys to any juicy character, whether it's Hamlet or Stanley Kowalski. Trent is not naturally a winner, but he's a winner in spite of his handicaps. I'm actually in therapy right now trying to figure this stuff out. Really. Because there was a lot of my childhood where I felt like something wasn't quite right, that I didn't fit."

He lived with his father and stepmother, who were both "kinda straight", in San Francisco, with a month's break in the summers to stay with is mother in New York. "I'd hang out with all her Bohemian friends, acting with them, drinking beer, smoking dope, kissing girls. Then I'd have to go back to San Francisco and be normal. I felt like an alien."

Rockwell has just completed work on Woody Allen's next, as yet untitled, feature, in which he sports a horrific bleached hairdo and stars alongside Leonardo DiCaprio and Kenneth Branagh. Now he's about to return to the New York stage as a breather from films - not because theatre is necessarily easier, but the idea of indulging in concentrated bouts of acting as opposed to spending 12 hours in your trailer to commit 10 minutes' worth of work to celluloid obviously has greater appeal. Rockwell is playing a racist car salesman in a New York production of Mike Leigh's Goose Pimples.

"The bastard improvised the whole thing," he laughs, "but it's us who have got to learn every damn `uh?' or `eh?' " He has perfected his London accent, he says, by watching old episodes of Only Fools and Horses. Lovely jubbly.

`Lawn Dogs' is reviewed overleaf.