But with the film's four-award sweep at the Golden Globes on Sunday, Danny Boyle's romance has completed the same rags-to-riches trajectory of its main character.
Like the underdog success of Jamal Malik - a poor kid from the slums of Mumbai who becomes a flawless contestant on India's Who Wants to Be a Millionaire - Slumdog is an unlikely triumph.
"This could turn into a $US100 million ($NZ190 million) movie now," said Paul Dergarabedian, president of box-office tracker Media by Numbers.
"It's like the snowball effect."
Its win at the Golden Globes will help secure its future, both as a box office success and as a major player at the Oscars, which will announce its nominees on January 22.
The Academy Awards will be held on February 22.
"It really gives the film credibility to people who maybe didn't know that much about it or didn't understand it," Dergarabedian said.
"Suddenly, this is like the stamp of approval. It creates a situation where people are going to have to see this film."
It also assures that Fox Searchlight will reinvest in marketing and expand the film's release to capitalise on its success. Slumdog was filmed in India with a budget of only $US14 million and has no big-name actors, and about a fifth of it is in Hindi.
"We really weren't expecting to be here in America at all at one point so it's just amazing to be standing here," said screenwriter Simon Beaufoy while accepting his Golden Globe on Sunday.
But since the film's North American limited release in 10 theatres in November, it has made $US34 million, garnered excellent reviews, strong word-of-mouth and numerous awards. The honours include the audience award at the Toronto Film Festive and best picture from the National Board of Review, an early harbinger of the Academy Awards.
Slumdog was originally to be released by Warner Independent Pictures, but Warner Bros closed that branch last year - leading to dim prospects for Slumdog, including a potential DVD-only release. But Fox Searchlight picked it up and is sharing costs and revenue with Warner Bros.
The studio, a boutique division of 20th Century Fox owned by News Corp, has been here before. It has engineered the unlikely awards campaigns for small independent films like Sideways, Little Miss Sunshine and Juno, all of which were nominated for Best Picture by the Academy. None of them won the top film award.
All took on a similar David-verse-Goliath image at the Oscars and went on to make a lot of money.
Sideways eventually made $US72 million, Little Miss Sunshine took in $US60 million and Juno made $US143 million.
Slumdog is currently in 601 theatres and has never been in more than 614 theatres in its nine weeks of release. By contrast, Bride Wars opened in 3226 theatres last weekend.) With low-budget awards-contenders like these enjoying box office success, suddenly the prospects of independent film don't look quite so apocalyptic as they did when divisions like Warner Independent and Picturehouse were shuttering.
"It's fantastic for us to have had this kind of platform," said Boyle, whose previous films include Trainspotting and 28 Days Later.
"It gets journalists all perked up. It works in so many different ways. It's an amazing vehicle for this kind of film - and this kind of film is under pressure, as we know. The indie distribution is in real crisis."
The Globes are far from a perfect predictor of the Oscars, though. And Slumdog almost certainly benefited from the more international outlook of the Hollywood Foreign Press voters.
But Slumdog no longer seems like much of an underdog.
"Slumdog has all the momentum right now. It's the film to beat," said Tom O'Neil, a columnist for the awards website TheEnvelope.com.
"It's captured Oscar voters' hearts. Many of the voters I've spoken to have watched their DVD screeners six or seven times."
Weeks ago - when such plaudits seemed pure fantasy - Boyle joked of the film's awards chances: "Obviously, we've got to win every single category. Obviously. And put Titanic to sleep for once and for all."
After winning in all four categories it was nominated for at the Globes, that no longer seems quite so farfetched.
