Imagine, if you will, that Terrence Malick decided to direct an instalment of the American Pie franchise. Further imagine that, rather than mould the project to his own transcendental purposes, Malick embraced the gross-out aesthetic with enthusiasm.

Something similarly dissonant occurred when David Gordon Green, young director of powerful, pocket-gothic pictures such as George Washington and All the Real Girls, ventured into stoner farce with Pineapple Express, Your Highness and The Sitter. It's hard to think of any arthouse director who has made that sort of shift.

"To me, it's surprising that he made those other serious films," Pineapple Express star Seth Rogen once told me. "We just know him as this crazy guy who makes these crazy films."

What does Green make of that assessment?

“That doesn’t surprise me at all,” he says in a calm, educated voice. “Just as Seth would get into character if he’s in more serious material, I am a different person when working on a different movie. If I was doing a horror film, I would show another side.”

This month, after dallying in low-brow territory for the past half-decade, Green, a 38-year-old Texan who enjoys a dry joke, sets out to rediscover his more offbeat roots. The cracking Prince Avalanche is definitely a comedy – Emile Hirsch and Paul Rudd play two chaps repainting road markings in land ravaged by forest fire – but it is a comedy of the most peculiar stripe. The dialogue meanders. The tone is often sombre. Based on an Icelandic film called Either Way, Prince Avalanche still emanates a dry, very Nordic class of wit.

“It was just a whim of an idea that we put together very economically,” he says. “It was a way for Paul, Emile and the rest of us to cleanse our palates. We didn’t really tell anybody aside from a few financiers. We were making something down and dirty that wasn’t accompanied by all these headlines about budgets and so on. We enjoyed it and believed in it.”

It sounds as if he and his crew were behaving a little like the two main characters: mucking about while isolated from civilisation. “Yeah, maybe,” he says. “I have done a lot of mundane jobs in my life. I could see these two guys as two bickering sides of my own character.”

David Gordon Green was born in Arkansas, but raised just outside Dallas in a well-off family: mum was a Lamaze instructor; dad was the dean of a medical school. After attending North Carolina School of the Arts, he set about funding his hugely acclaimed, inspirational debut feature film George Washington (which doesn't really have anything to do with George Washington). He admits to the influence of Malick, but Green's school of dreamy melancholy was all his own. The equally highbrow Undertow and All the Real Girls followed.

For some time he was associated with a film version of John Kennedy Toole's great comic novel A Confederacy of Dunces starring Will Ferrell. It was on. It was off. It was on. Now it seems very off.

“I think it’s definitely dead now,” he says with a cheery swagger. “My involvement in it certainly is. The problem is that, once you get the rights to a something, it suddenly becomes very hectic. You have a certain window and then people cease to become available. You open up this project and live in it for years. I moved to New Orleans. I researched.”

After all that, it must have been devastating when A Confederacy of Dunces didn't happen. He had given his life to it.

“Oh, not really,” Green says. “The scouting brought new experiences. I learnt a lot. You take that frustration and direct the resulting energy into new projects. The ones that don’t happen weren’t meant to happen. That’s the way to think of it.”

On this occasion, the energy was directed into comedies that found the likes of Jonah Hill, Seth Rogen and Danny McBride smoking weed and befouling sofas. Was that a conscious decision or did he just drift towards the lighter stuff? Maybe, bad influences led him astray.

“I sought out that transition in my career,” he says. “I was working in a very dramatic form. That put my head in a very dark place. I wanted to make something audiences were eager to see, rather than something you had to twist their arms to get them to see. I had been living with a lot of bleakness. And I am not a bleak guy. I like hanging out with my friends. I also had to be conscious of not exhausting my dramatic muscles.”

Now, this is an interesting comment. Green is suggesting that an artist can draw too heavily from a particular aesthetic well. Work too hard at the grim drama and you may exhaust your capacity for that genre.

"Yes. I think so," he says. "And the other drawback is that you can become branded as a film-maker. Some directors set out to create brands. I love the idea of trying different types of films. It would be hard for David Fincher to make a romantic comedy. But I can do that."

The old David Gordon Green is definitely back. Prince Avalanche – a comedy that will appeal to fans of Magnus Mills's Restraint of Beasts – premiered at Sundance in January. Last month, his latest film, Joe, screened to great acclaim at the Venice Film Festival. An adaptation of a novel by Larry Brown, the picture features a much-praised performance by Nic Cage.

“He was an idol when I was growing up,” Green says proudly.

Still, from what he says, Green has no intention of abandoning the mainstream. Why would he? The disgraceful, disreputable Your Highness – a sort of medieval drug romp – brought him to lovely Northern Ireland. Now there's a privilege.

“Shooting there was one of the highlights of my career,” he raves. “There is no better place than Belfast to go for a drink after work.”

The shoot did the North’s film industry no harm. Shortly after Green wrapped, a certain epic TV series moved in.

"I only watched Game of Thrones recently and I suddenly noticed they were using some of our sets," he says. "We put them out for the trash and they saw them and thought: 'Ah ha!' I am not altogether sure what I think about that."

Send them a bill.