William Friedkin: 'We don't set out to promote violence'

William Friedkin belongs to that hallowed group of American directors (Terrence Malick, Martin Scorsese and Francis Ford Coppola among them) who in the 1970s produced works of such power and verve they guaranteed that every film they made after – whether good or bad – would be seen as an event.

Now 76, the Chicago-born director of The Exorcist is back with a new film. Killer Joe is, like his last feature film, Bug in 2006, an adaptation of a Tracy Letts play. When the play was performed in London in 1995, the black humour and violence of the piece saw Letts grouped with in-yer-face theatre practitioners, Sarah Kane and Mark Ravenhill. Friedkin, as is his wont, has taken the text and with the help of Letts injected it with more characters and revised scenes.

"I think that he is the best drama writer in the United States and he has a unique way of capturing sides of human nature that you don't often see – honestly portrayed and without any judgement," says Friedkin of the collaboration. "He and I are sort of on the same page with our world view. Now, don't interpret that as meaning we think the world is shit or something like that, we think there is good and evil in everyone."

In fact, the scoundrels on show in Killer Joe are mostly bad. Emile Hirsch plays debt-ridden Chris who comes up with an insurance scam that involves hiring a hit man, Killer Joe Cooper (Matthew McConaughey), to murder his promiscuous mother (Gina Gershon). When money is hard to come by, Chris thinks nothing of Killer Joe wanting a piece of his 20-year-old sister (Juno Temple) as recompense.

Violence and mayhem ensue. Which seems a fair interpretation of the film, except that Friedkin doesn't agree: "It's not very violent," he protests. "If you want to see violence, go see Transformers, where that Megatron guy kills thousands of people or any of the other films that are rated PG for children. The reason that you might think that there is violence in Killer Joe is that the violence appears to be real, but we don't set out to promote violence. And I don't happen to like it."

The director does, though, believe that violence is an integral part of great drama. From his childhood onwards, he says, violence was part of his everyday life: "I've seen it, I grew up in a very large apartment building in Chicago, and when I was a child there was casual violence on every floor – family violence, not robberies or murderers, but within families. It wasn't in my family, I must say, I love my mother and father and have a very wonderful relationship with them, but I saw it as I grew up."

His father was a semi-pro softball player and merchant seaman who ended up working in a men's clothing store. His mother was an operating room nurse. After watching Citizen Kane the teenaged Friedkin became infatuated with movies and Orson Welles. He got a job in television straight out of high school and soon was making documentaries. His rarely seen debut, The People vs. Paul Crump, about a young man on death row in an Illinois prison, won an award at the 1962 San Francisco Film Festival.

In 1972, he won the best director Oscar for The French Connection but it was his 1973 hit The Exorcist that guaranteed his place in cinema lore. Almost 40 years have passed since the seminal horror came out. "It's an absolutely great movie," asserts Friedkin today. "Just ask your public! The reason it's a great movie is the writer's faith and belief in the story. The film was never conceived to be a horror film, it's easy to dismiss it and call it that, it's a film about the mystery of faith, and there are not many films about that. Because of its script and because of the perfect cast that I was blessed with, it's a film that lives."

The director has always had a reputation for being combative and self-confident, even when his career began to slide after Sorcerer in 1977, a misbegotten remake of Henri-Georges Cluzot's The Wages of Fear. In 1980 he wrote and directed Cruising, starring Al Pacino, which sparked controversy with its depiction of the gay community in New York City. The scriptwriter Joe Eszterhas wrote in his memoir that he considered Friedkin to be a has-been when he was ordered by Paramount, headed by Friedkin's fourth wife, Sherry Lansing, to let him direct Jade in 1995.

Since 1996 he has forged a second career directing operas. At the end of last year he staged Janacek's The Makropulos Case in Florence and in March The Tales of Hoffman in Vienna. The latter demonstrated that the director has lost none of his talent for getting into disputes. He was due to return to Vienna with the opera after its initial sell-out run, but after mixed reviews, Roland Geyer, the Theatre an der Wien boss, fired him and put himself in charge. Friedkin retorted by calling him a liar.

Today, he has mellowed a little with age. Looking back over his career, he says: "I don't see myself as a pioneer. I see myself as a working guy and that's all and that is enough. I love to direct films and I love to have the opportunity to direct them and I know they are of varying quality but I don't know that when I do them. It's years later where I figure out where I may have made missteps or not."

Killer Joe is a welcome return to cinematic form for Friedkin and, like much of the director's best work, it's the atmosphere and tension he creates as much as the plot that's so riveting. The central romance between McConaughey and Temple is electric despite the moral ambiguity. It's exactly these human conundrums that continue to drive the film-maker to direct. "She's a Cinderella character who is looking for a Prince Charming and he happens to be a hired killer," he says. "I'm not interested in Transformer movies and stuff like that. I'd rather make a film about human drama and the comedy of life."

As The Exorcist's Father Merrin would say: Amen to that.

'Killer Joe' opens the Edinburgh International Film Festival tomorrow; it is released nationwide on 29 June