Jake Gyllenhaal has become a fixture at the Toronto International Film Festival. Over the last four years, the actor has appeared there with a series of chameleonlike performances in “Nocturnal Animals,” “Demolition,” “Nightcrawler” and “Prisoners.” This week, he heads back to Canada with “Stronger,” the story of real-life Boston Marathon survivor Jeff Bauman.

“Stronger” is a harrowing showcase for Gyllenhaal, playing a 27-year-old man who loses both his legs in the 2013 bombing on Boylston Street. The movie, which opens in theaters on Sept. 22 through Roadside Attractions, signals a behind-the-scenes transformation for Gyllenhaal. It’s the first project that he has produced through his Manhattan-based company Nine Stories (named after the 1953 collection of prose by J.D. Salinger), which he launched two years ago with veteran producer Riva Marker.

“We have two goals,” says Gyllenhaal, seated next to Marker in their new offices in SoHo in downtown New York. “One is to find material I can do as an actor. And also, it’s to champion the filmmakers we love.” He notes that when he’s not appearing in a project, he’ll be involved behind the camera only.

Nine Stories’ game plan is to back edgy, independent films in the $10 million-to-$40 million-budget range, TV series and stage productions (such as “Sunday in the Park With George,” starring Gyllenhaal, which had a limited, sold-out run on Broadway in the spring). Many of its film titles are financed through a first-look deal with Bold Films, an agreement that was recently extended through 2020. “They have so much passion and such great taste,” says Gary Michael Walters, the CEO of Bold Films. “They have very quickly evolved into true producers.”

Jake Gyllenhaal started Nine Stories to produce edgy tales.

Mike McGregor for Variety

The world of independent film is one of feast or famine. Money is freely flowing into productions, thanks to the influx of digital players like Netflix, Amazon Studios and Apple, which is entering content creation. At the same time, it’s never been harder to sell tickets to smaller and midsize movies, which are fighting to keep up at the box office.

“I feel like it sort of is the best of times,” says Marker, the producer behind such indie films as “Hello, My Name Is Doris” and “Beasts of No Nation.” “I think the market does feel flush with cash. But also, because we’re living in such a dark time politically, people really are looking to the arts, especially when you have an administration that wants to pull back on it.”

Nine Stories’ slate is a robust mix of sizes and genres (including the Tribeca documentary “Hondros,” about a celebrated war photographer, which sold to Netflix in the spring). The company just closed a deal with Fox Searchlight for the next movie from “The Big Sick” director Michael Showalter, called “The Last Ride of Cowboy Bob.” Based on a Texas Monthly article, it tells the story of a female bank robber in the ’90s who got away with her heists by dressing up in men’s attire. “It’s an opportunity for a tour de force role,” Marker says. “It’s a woman playing a man.”

Gyllenhaal says one of his missions as a producer is to elevate projects with female leads and directors. “My sister happens to be an actor,” he says of Maggie. “She’s the person I always looked up to since I was little. And my mother” — Naomi Foner — “is a very strong, powerful, talented writer. I’ve been raised by these incredible female storytellers, so it’s natural for me to say, ‘Where are those stories?’”

Also on tap at Nine Stories is “The Son,” to be directed by Denis Villeneuve, with Gyllenhaal portraying a man who confesses to crimes he didn’t commit; “The Anarchists vs ISIS,” based on a Rolling Stone article about a ragtag group of Americans battling the terrorist group; Luca Guadagnino’s drama “Rio,” with Benedict Cumberbatch and Gyllenhaal; and “The Good Time Girls,” the directorial debut from costume designer Courtney Hoffman, starring Laura Dern.

Gyllenhaal, who now reads roughly 250 scripts a year, got the producing bug during a time of restlessness in his career. Unfulfilled by studio tentpoles, he started to experiment in the indie space with dramas like David Ayer’s “End of Watch,” for which he received his first producing credit in 2012. On that film, he learned the important lesson of collaborating with a director at the right time, on his way up, when the costs of a budget can still be kept down.

“For me, it’s not about anything up front,” Gyllenhaal says about taking a reduced salary as an actor. “You put in your preparation and hustle. When we made ‘End of Watch,’ David Ayer and I said to each other, ‘Let’s do it out of the earshot of everybody in a small space.’ The same with Dan Gilroy.” His thriller “Nightcrawler,” with a budget of $8 million, went on to gross $50 million worldwide.

Those successes drove Gyllenhaal to launch his own company. But he needed a partner, and he struggled with the idea of working with a total stranger. Graham Taylor, a top agent with WME, suggested that Gyllenhaal meet with Marker, on a hunch that they would get along. “I felt the two of them would be the Starsky and Hutch or Laverne and Shirley,” Taylor says. “They were like two halves of a locket. They seemed like the obvious pair to put together.”

Riva Marker has a knack for making challenging indies.

Mike McGregor for Variety

It was a blind date that led to a happy working marriage. Their first conversation was so easy, it was like they’d known each other for years, as they bonded over their favorite ’80s films. Marker had experience making tough movies. For “Beasts of No Nation,” she was one of the producers who spent three years with director Cary Fukunaga, who filmed in Ghana under treacherous conditions involving snakes and malaria.

For “Sunday in the Park,” Marker enlisted Fukunaga to shoot a video of Gyllenhaal belting out “Finishing the Hat” that became the show’s viral marketing campaign. She had one day to figure out a way to hang Fukunaga from the rafters of the Hudson Theatre so that he could get the extended shot he wanted.

Gyllenhaal and Marker’s rapport is on full display in their joint interview with Variety. He talks about how he’s sent her text messages at 3:30 in the morning, while shooting a movie overseas, and she’s responded immediately. “People say to me, ‘You work so hard,’” he says. “I sleep. She never sleeps!”

“I sleep,” Marker insists. She says she gets six hours a night — although they might not be consecutive.

The Making of ‘Stronger’

“Stronger” required a Herculean effort to get to the big screen. Producer Todd Lieberman had optioned the rights to Bauman’s story, developing it at Lionsgate with Gyllenhaal in the lead role. But after the studio partnered with CBS Films to release “Patriots Day,” starring Mark Wahlberg as a Boston police sergeant in the aftermath of the attack, there was concern the two films were too similar. “It started to feel like it was slipping,” Gyllenhaal says. “We were the smaller movie.”

Just after starting Nine Stories, Gyllenhaal went to Bold Films in October 2015 with a pitch to see if it would finance “Stronger,” with him and Marker as additional producers. “It was a great fit for a number of reasons,” Bold’s Walters says about the project, which had a $30 million budget. “We are aspiring to make larger movies.” Lionsgate stayed on as the film’s distributor, with Roadside partnering later on the domestic release.

Gyllenhaal spent days in Boston with Bauman to capture his likeness (even watching how he picked up a fork). It was important for him to get his story right. “I started to understand Jeff psychologically through his speech,” Gyllenhaal says. “He constantly has an inviting quality to him. Always open. Always childish. That childish aspect made him a survivor.”

Gyllenhaal conducted extensive research to play Jeff Bauman in “Stronger.”

Mike McGregor for Variety

Bauman recalls how Gyllenhaal would drive up from New York. “He did a lot of research,” Bauman says. “We went over a lot of physical stuff, like what hurt. How I would sit up, how I would take my legs off, stuff like that, which was really interesting to show him. Not a lot of people asked questions like that.”

Gyllenhaal had to portray the character knowing that both his legs would be digitally erased later on. “We had to plan,” Gyllenhaal says. “It’s a mixture of prosthetics, holes in the floor and visual effects.” He’d often sit in a wheelchair with his legs tucked under him, and he’d wear green socks for the special effects. “The team would come over and have these little white stickers, and they would tape them all over my legs,” he says. “I can’t tell you how many nights I would wake up with a sticker in my hair.”

Between takes, Gyllenhaal attended production meetings, scouted locations and weighed in on the film’s poster. He said that as a producer, he felt more pressure to deliver a movie that was financially successful. “This thing doesn’t work, it’s on your ass,” he says.

At least he won over an important viewer. In June, Bauman saw a finished cut of the film. “I don’t want to brag about him, but he’s amazing,” he says of Gyllenhaal’s performance. “I have a lot of amputee friends, and they saw the previews and asked: ‘How did he do that? He looks just like you.’”

After Toronto, for the first time in five years Gyllenhaal is giving himself a short break from his day job. “I’m taking the fall off as an actor,” he says. “We’re just going to focus on the company.”