Jack Twist is a fictional character in the short story "Brokeback Mountain" by Annie Proulx, the 2005 Academy Award-winning film adaptation of the same name directed by Ang Lee, and the 2023 play by Ashley Robinson also adapted from the short story.

[1] Jack's story primarily follows the complex sexual and romantic relationship he has with Ennis Del Mar in the American West from 1963 to 1983.

In an interview about her work, and "Brokeback Mountain" in particular, author Proulx stated that Jack Twist is a "confused Wyoming ranch kid" who finds himself in a personal dilemma he did not foresee, nor can understand.

"[4] The film's producer James Schamus and LGBT non-fiction author Eric Marcus opined that the characters were both gay.

Hartinger personally "felt it inconceivable" that the characters could be considered bisexual and not gay because the film consistently showed their dissatisfaction with their heterosexual partners and deep emotional and physical fulfillment with one another.

For Hartinger, the actors' opinions of "straight guys who just happened to fall in love" seems to come more from Gyllenhaal and Ledger's acting method rather than an assessment of the text.

In 1963, while working as a rodeo cowboy on Brokeback Mountain, Wyoming, Jack encounters Ennis Del Mar, a ranch hand portrayed by Heath Ledger in the film adaptation.

One night, after sharing whiskey, Ennis decides to stay overnight at the base camp due to cold weather.

Jack moves to Texas, marries Lureen Newsome (played by Anne Hathaway), and has a son named Bobby with her.

Jack proposes building a life together on a small ranch, but Ennis, fearing societal consequences, hesitates.

Months later, Ennis learns of Jack's death, allegedly in a tire-changing accident, but suspects foul play due to their secret relationship.