TORONTO—From his turns in mind-fuck films like Shutter Island and Eternal Sunshine of the Spotless Mind to a best-supporting-actor Oscar nomination for The Kids Are All Right, Mark Ruffalo is one of those rare character guys who quietly make good films even better.

His newest performance, in the Oscar front-runner Foxcatcher (opening November 21), is no different. The film, the third feature by director Bennett Miller (Capote, Moneyball), revolves around the true story of troubled heir John du Pont (a darkly serious Steve Carell) and his obsession with funding an Olympic gold-medal wrestling team led by brothers Mark (Channing Tatum) and David Schultz (Ruffalo). Much of the attention is being directed toward the transformations undergone by his costars—physical for Carell, careerwise for Tatum—but Ruffalo is once again a steady presence and a solid bet as an Oscar contender.

As a wrestler during his high-school years, the Wisconsin native felt a personal connection to the subject. “It was a big part of my life; I learned a lot about life and adversity and being alone,” said Ruffalo, speaking to the Georgia Straight in a downtown hotel room during the Toronto International Film Festival. “I also understood what the life of a wrestler was like and how lonely it was and how constant. The season never stops. It’s all year long. I remember never really being able to eat turkey at Thanksgiving because there was a match a couple days later. From 13 to 17, to live like that was intense as a kid and those guys lived like that their entire lives. So I understood what it was like to be a wrestler, which helped me.”

When asked—during a separate interview—about casting, director Miller provided lengthy explanations for choosing Carell and Tatum. Not so much for Ruffalo. “Well, Mark Ruffalo is Mark Ruffalo; it requires no explanation,” the filmmaker gushed. “He’s just got the biggest heart of anybody I’ve ever met and I was just, like, ‘Well, there’s no movie without him.’ ”

Although the events described in the film actually happened, exactly how they happened is unclear (most of the people involved have since died), leaving the cast and crew space for creativity. “I’m always surprised by playing a real person,” Ruffalo said. It’s nothing new, as the actor has portrayed real people before and will take on the lead role in Spotlight, the upcoming drama about Boston Globe scribe Michael Rezendes’s takedown of the Catholic Church.

Quiet talk doesn’t usually hold the attention of a group of journalists and critics, but one could hear a pin drop as Ruffalo articulated, his raspy voice low and soft, the process of turning nonfiction into a creative work. “Shakespeare does a great job of taking 5,000-year-old stories and turning them into modern pieces that are true to the original essence but are completely remade,” he said, “and that’s kind of how this feels. It’s a true story but it’s lifted up into the eternal, the universal.”