Diana Ossana discovered Annie Proulx's short story in October 1997 just days after publication, and convinced writing partner Larry McMurtry to read it, who called it a 'masterpiece'.

Gus Van Sant originally attempted to make the film, hoping to cast Matt Damon and Joaquin Phoenix, and also considered Leonardo DiCaprio, Brad Pitt and Ryan Phillippe, but most stars he approached were uncomfortable with the homosexual material.

Matt Damon turned down the project by telling Gus Van Sant he couldn't follow up a gay movie and a cowboy movie with a 'gay-cowboy movie'.

Pedro Almodóvar was initially offered the chance to direct but turned it down citing concerns about artistic freedom, and Ang Lee only committed to the project after finishing Hulk left him considering retirement.

The studio initially thought Heath Ledger, suggested by the screenwriters after his performance in Monster's Ball, was not masculine enough for the role, but he pushed to be cast after finding the script 'beautiful'.

Mark Wahlberg met with Ang Lee for a role but declined because he was 'creeped out' by the script.

Anne Hathaway auditioned for Lureen during her lunch break while filming The Princess Diaries 2, still wearing an over-the-top ball gown and hairpiece, and lied about knowing how to ride horses, later taking two months of lessons to prepare.

Although the story is set in Wyoming, the film was shot almost entirely in the Canadian Rockies in Alberta for financial reasons, with the mountain in the film being a composite of Mount Lougheed, Fortress Mountain and Moose Mountain.

Alberta's environmental department initially banned domestic sheep from the Rockies due to disease risk to wildlife, eventually allowing filming on one mountain only if the sheep were transported in and out daily under a biologist's supervision.

The first sex scene between Ennis and Jack took 13 takes to satisfy Ang Lee, who kept his distance from the actors during shooting to let them be spontaneous.

Michelle Williams sprained her knee early in filming, forcing her character's movements to be altered so she mostly sat or stood; Heath Ledger injured his hand punching a wall for a scene and nearly broke Jake Gyllenhaal's nose during a kissing scene.

The American Humane raised concerns about animal treatment during filming, alleging sheep were handled roughly and that an elk was shot with anesthetic on cue, violating standard animal-handling guidelines.

Composer Gustavo Santaolalla was able to score much of the music before filming began, based on the story and a single conversation with Ang Lee.

For the film's theatrical poster, producer James Schamus took inspiration from the poster of James Cameron's Titanic, which depicts two star-crossed lovers.

The word 'brokeback' entered Chinese slang as a term for homosexuality, and the film was banned from Chinese theaters, though widely available on bootleg DVD and VHS.

In 2008, Italian state television channel Rai Due aired a censored version removing all homoerotic scenes, sparking viewer protests before RAI broadcast an uncensored version in 2009.

The shirts worn by Ledger and Gyllenhaal's characters were sold on eBay in 2006 for $101,100.51 to benefit a children's charity, with the buyer comparing them to the ruby slippers from The Wizard of Oz.

Randy Quaid, who played Joe Aguirre, sued Focus Features in 2006 claiming the studio misrepresented the film as a low-budget art house project with no profit potential to secure his services cheaply; he later dropped the suit after reportedly receiving a settlement.