A fan of sports movies from Bad News Bears to North Dallas Forty, Brad Pitt said he was inspired to make the film Moneyball because he's "a sucker for an underdog story."

The Hollywood star, his Moneyball castmates and director Bennett Miller spoke about the forthcoming baseball tale on Friday in Toronto, where the movie is screening as part of the Toronto International Film Festival.

Based on a book by Michael Lewis, Moneyball tells the story of former player-turned-general manager Billy Beane, who adopts an unconventional and unpopular system in order to transform a team of undervalued, misfit players into a winning lineup for the Oakland A's.

"It's a story about our values: how we value other people, what we value as success, what we value as failure," Pitt said during a packed media conference at TIFF Bell Lightbox.

'I couldn't let go of the story about these guys who, by necessity, were trapped in an unfair game.'—Brad Pitt

Premiering as one of Friday night's red carpet galas at TIFF, Moneyball had a tough journey to the big screen, with several different producers, directors and writers joining and leaving the project over the years.

"It's complicated material. It's not your conventional story or storyline with a conventional character arc," explained Pitt, who also served as a producer of the film.

"So it took a lot of shots at it and a lot of people getting their fingerprints on it and trying to figure out what this thing would be.... Ultimately, I couldn't let go of the story about these guys who, by necessity, were trapped in an unfair game."

The themes of acceptance and reinvention run through the film, which also stars Jonah Hill, Philip Seymour Hoffman, Robin Wright and Chris Pratt, who praised the real-life baseball players that appear in the movie and served as consultants.

"This film is very authentic to the sport of baseball," the actor from TV's Parks and Recreation said, noting that athletes in the cast had played in the major, minor and college leagues or in the farm team system.

"Every bit of baseball you see is real. I would take this baseball team against any other baseball team from any other baseball movie ever and we would kick their asses. These are real baseball players and being a part of that was really inspiring."

Asked about the enduring appeal of depicting "America's sport" on film, Miller spoke of the game's many layers.

"Some think that you can reduce and distill this thing and understand it on a physical level so you can predict the outcomes to a finer and finer degree. But it is also a game that has — I think — more superstition than any sport ever," he said.

"Inexplicable things do happen in this game," he continued. "The moment you think you have got a grip of the game, it defies you. Magical things happen."