Today, his zombie movie is a global hit, having grossed more than $536 million around the world. But Pitt’s production of “12 Years a Slave” might end up being even more commendable, as the true account of Solomon Northup, a free man sold into slavery, has become the runaway critical hit of the Telluride and Toronto International film festivals.

As Pitt said in Telluride, where “12 Years a Slave” enjoyed its world premiere, “This is why we got into the film business in the first place. I wanted to be a part of it.”

WATCH: Trailers from Toronto

With his Plan B partners Dede Gardner and Jeremy Kleiner, Pitt pursued writer-director Steve McQueen in the wake of his feature debut, 2008’s “Hunger.”  The British filmmaker said he wanted to make a movie about slavery and eventually brought Plan B the memoir by Northup. McQueen collaborated with screenwriter John Ridley (“Red Tails”), while Plan B did the difficult work of raising the film’s $22-million budget, which allowed for 35 days of shooting.

Pitt and his partners fought to make sure McQueen had enough money to realize his vision for the film. Hollywood’s big studios weren’t inclined to back the film, even with Pitt playing a small role as an abolitionist-inclined carpenter. “It was not what the studios were looking for,” Pitt said. “For them, it’s all about tent poles.”

But even some independent financiers were skeptical. “Of course, the natural reaction is, ‘Make it cheaper, cheaper,’” Pitt said of what some potential backers wanted.

Plan B cobbled together the financing with Bill Pohlad’s River Road Entertainment (which backed Pitt’s “The Tree of Life” with Terrence Malick), New Regency Pictures (which had made “Mr. and Mrs. Smith” with Pitt and Angelina Jolie) and Britain’s Film 4. Fox Searchlight is distributing “12 Years a Slave” domestically.

Plan B is wrapping up the journalism drama “True Story” withJonah Hill and James Franco, and is preparing to shoot “The Lost City of Z,” which stars “12 Years a Slave” costar Benedict Cumberbatch as a British explorer who goes missing in the 1920s.

There’s little doubt “12 Years a Slave” will be at the center of the awards season, but Pitt hopes that people who see the film will think not about Oscars but loftier ideals.  “It illustrates man’s inhumanity to man,” Pitt said, “but also reminds us of our responsibility to each other.”

Even Pitt acknowledged in Toronto that "12 Years a Slave" could be hard to top.

"If I never get to participate in a film again..." he said at a question-and-answer session, before trailing off, "this is it for me."