In Southpaw, anger is Jake Gyllenhaal’s strength – and his weakness

Acting is a therapy for the actor who stars as a troubled boxer in the movie.

From left, Miguel Gomez as Miguel Escobar, Beau Knapp as Jon Jon, Jake Gyllenhaal as Billy Hope and Rachel McAdams as Maureen Hope in Southpaw. Scott Garfield / The Weinstein Company via AP

Jake Gyllenhaal laughs with embarrassment as he tells me about the first time he met boxing coach Terry Claybon.

The young actor had been hired to play fictional boxer Billy Hope in Antoine Fuqua's bruising drama, Southpaw, and Claybon – who trained Denzel Washington when he starred as real-life boxer Rubin Carter in 1999's The Hurricane – wanted to see him shadowbox.

“I was like, ‘Oh [no]’,” says Gyllenhaal. As he weakly punched the air, Claybon’s jaw dropped. “He let me do it for, maybe, like, a minute-and-a- half – it felt like an eternity – and then he was like, ‘Hell no!’”

Fortunately, Fuqua had faith in Gyllenhaal, and the actor repaid it in spades.

For months, he completed twice-daily training sessions in the gym, went on runs and sparred with professionals. Such was his focus on the role that his relationship with his girlfriend Alyssa Miller fell apart.

The result Gyllenhaal achieves is not only impressive in its right but, when viewed alongside his emaciated appearance in last year's Nightcrawler, it is astonishing. Ripped and nimble, his Billy Hope looks like he could stand his ground against any real-life middleweight.

Anger is Hope's strength – and his weakness. Inside the ring, it makes him unbeatable. Outside, it is his downfall. This fascinated Gyllenhaal, who played a United States Marine in 2005's Jarhead at a time in his life when he constantly felt like, "I wanted to punch my first through a wall".

The 34-year-old remains fascinated by where his anger comes from, and saw playing Hope as a way to explore it safely.

“I’m very curious about what sets me off,” he says. “Sometimes it’s baffling to me. I wonder what those feelings are and I’m interested in them.”

Gyllenhaal doesn’t think of himself as an angry man. He had a privileged childhood in LA, where he and his actress sister Maggie were raised by a film-director father and screenwriter mother, surrounded by colourful industry folk.

One day, Paul Newman took Jake around a racing track, which later got turned by journalists into a story about the Hollywood legend teaching him to drive. “My father really taught me how to drive and he’s getting a really bum rap,” Gyllenhaal once told me.

He concedes that he enjoyed privilege as a child – but “no one”, he says, “had a great childhood, no matter what they say. Even though we all pretend that we want to go back and be children again, I don’t think we would really want to”.

He finds acting to be therapeutic, and looks for material that will take him “to places that are challenging, even for yourself ... I like the idea that you can use your work to make you go, ‘Wow, I never really saw the world this way. I sat wherever I sat in my place, having some sort of judgement, and now I no longer have that’”.

For a while, he stopped listening to himself and lost his way in his career. In 2009, his parents divorced, and he took stock of where he was.

“I was a little unclear about what I wanted to say and how I wanted to even just live my life and where I wanted to be,” he says.

He moved to New York, closer to the world of theatre, which he loves, and shifted his focus to independent films. In 2012, the gritty cop thriller End of Watch marked the beginning of what is becoming a golden period for Gyllenhaal. Films such as the doppelganger head-scratcher Enemy, and the disturbing crime drama Prisoners, hark back to the days before he dabbled in blockbusters such as The Day After Tomorrow and Prince of Persia, and could do something weirder like Donnie Darko.

Scaling down and working with more collaborative filmmakers who give him room to be creative has resulted in some of Gyllenhaal’s finest performances to date.

“There’s been a real artistic freedom,” he says, “particularly with the last number of directors I’ve worked with.”

His new film, the real-life survival story Everest, will open next month's Venice Film Festival. Typically, Gyllenhaal pushed himself to the limit for one scene by allowing himself to be buried in snow for so long that he almost lost his hearing.

Whether Everest can live up to his recent run of movies remains to be seen. There is no question, however, that in rediscovering his voice, Gyllenhaal has become one of the most exciting actors working today.