Asked how his youth impacted the whole process of making his debut feature, Xavier Dolan is nothing if not astute. “I will say that in the pre-production and production process, my youth was always a flaw for people,” says the actor and filmmaker in a recent phone interview from his home in Montreal. “But for the promotion, it’s a perk.”

Even Dolan understands he’s got a killer backstory, one that has been getting better known since I Killed My Mother (J’ai tué ma mère) became one of the best-received titles at this year’s Cannes Festival. His film makes its English Canadian premiere at the Toronto International Film Festival on Sept. 15.

A former child actor, Dolan was until recently best known in his native Quebec for a series of commercials for the Jean Coutu pharmacy chain. Anglo horror fans may have also spotted him as an early fatality in last year’s Martyrs. (When I mention the movie, he expresses his embarrassment at sporting a “vagina haircut from the ’70s.”)

Dolan claims to have been raised on sets and soundstages, so perhaps it was only natural for him to write his first feature film script at the age of 17, having been inspired by aspects of his own tumultuous upbringing and experiences as a gay, teenaged Cocteau obsessive. Denied funding by the national and provincial film funding agencies, he poured over $100,000 of his own savings into the production. Besides playing his onscreen alter ego Hubert opposite Quebec TV star Anne Dorval as his mother Chantale, Dolan directed the movie.

Though he had taken no film classes nor made any short films before this attempt, the project was not the disaster one might’ve expected. Rough-hewn and flawed as the movie may sometimes be, it is also bold, brave and brimming with raw vitality.

I Killed My Mother was then selected for the Directors’ Fortnight at Cannes, an incredible piece of good fortune for any filmmaker, never mind one who was just turning 20. “The only thing I allowed myself to dream of was going to Cannes,” says Dolan of his original goals for his movie. “I never dreamed of any kind of glory or public enthusiasm — I didn’t go that far in my positive thinking. I only thought if I can go to Cannes, that means important people whom I respect and whom I have a lot of admiration for believed the film had the potential to be among all those amazing movies. That was the honour. The rest is just icing on the cake.”

Icing may not be half as sweet as what I Killed My Mother earned: a lusty standing ovation, three of the Fortnight’s four main prizes and distribution deals in over 10 countries. Such was the deluge of praise and buzz, even Brad Pitt’s people wanted to know about Dolan’s next move.

Meanwhile, the film’s young creator was shocked to discover that his sometimes ferocious, sometimes tender tale of mother-son warfare was connecting with viewers worldwide.

“The movie is really personal,” he admits, “and I thought it might be very hermetic in that nobody would connect with the story or understand things or the emotions of the characters. I thought it could be misunderstood. Then people read the screenplay and some of them did like it, but I thought maybe it was just for French Canadians! Then we went to Cannes and I realized that people from all over could identify themselves in the dynamics and the bonds I’m talking about in the movie.”

Yet, at the same time, I Killed My Mother is hardly one of those reassuring, audience-friendly little movies that have made “indie” nearly synonymous with “cuddly.” As Dolan says, “I don’t think it is a feel-good movie or a crowd-pleaser.” In fact, its anger and abrasiveness are its most attractive qualities, what with Hubert and Chantale spending much of the movie at each other’s throats. Neither party comes off as saintly — if anything, these monsters deserve each other.

“Yes, they can be awful,” the filmmaker admits. “It was important that they both be flawed so that the viewers could love and hate each of them by turn. The fact that they can be kind or mean or tender or brutal, I think that gives them texture and credibility — they seem alive.”

In that respect, Dolan has clearly learned some important lessons from the films he most admires, a list that includes My Own Private Idaho, In the Mood for Love, The 400 Blows, Pierrot le Fou and Magnolia. (He also adores many of the French-Canadians who were heroes at Cannes in an earlier age, filmmakers like Michel Brault, Claude Jutra and Gilles Carle.) And if, he attests, cinema is most valuable when it’s truest to our experiences, “you’ve got to be faithful to what life is really about. I’m young and I don’t know a lot of things but I know there are brutal things and darker feelings in life — so why not express them?”

While Dolan’s not the first young artist to venture into the world with such noble ideals and grand ambitions, it’s harder to find one so willing to take great personal and financial risks to fulfill them. Nor should his precociousness be mistaken for preciousness: there’s a hard-nosed sensibility behind I Killed My Mother’s occasionally florid gestures.

“The process of writing the movie was a really cathartic process,” he says, “but when I finished the screenplay and started shooting, it became a professional exercise. It was no longer some kind of therapy — it was really an artistic project.”

In the early days of the project, he says, “there were a lot of closed doors and hung-up phones. But, you know, fuck them. The important thing was that some people believed in it from the beginning. Even if yes, I had no experience, yes this, yes that, some people did dive into this weird ambitious venture with me. That gave me all the adrenalin and courage I needed, to know that other people believed in me and said, ‘Yes, we’ll go, we’ll do it, we think that this could be something. And we’re going to back you on this.’”

That Dolan made good on their hopes by crafting such a strong debut is impressive enough. All the rest is icing.