Aron Ralston filmed a daily video diary while he was stuck in the canyon; parts of the video diary were shown on a televised special about his entrapment, however most of the footage has only been shown to close friends and family and is kept in a bank vault for safety. Before shooting began both James Franco and director Danny Boyle were allowed to view the footage in order to accurately portray the events in the movie.

The camcorder used by James Franco in the film was the actual one Aron Ralston used when he was trapped in Blue John Canyon.

Since Ralston did not tell anyone that he was going hiking, no one knew that he was missing or even where to look for him. However, the moral of his story is lost on readers of his biography and audiences of the ensuing movie. One of them, 64 year old Amos Wayne Richards ventured to the same spot Ralston did and he did it without telling anyone. While 60 feet down a 70-foot-deep ravine, Richards slipped and fell the last 10 feet to the bottom. During the fall, he dislocated his shoulder, bumped his head on a rock, and broke his leg. It took Richards four days to crawl out of the ravine, and by the time the park rangers found him, he had already finished all of his water. In the end, it was the collective dumbness of 127 Hours fans that saved Richards. The park rangers at Blue John Canyon realized that Richards was missing because they were used to the influx of hiking enthusiasts to the canyon since 127 Hours was released. In fact, since 2005 (Ralston's biography came out in 2004), more than two dozen rescues have been performed in that same area - between 1998 and Ralston's incident, that number was "none."

For the moment when Aron falls down the canyon and gets his arm stuck under the rock, Danny Boyle filmed James Franco for 20 minutes straight going through all kinds of emotions. He then cut the material the way it ended up in the movie.

James Franco hid his textbooks in the crevices in the "canyon" set, to help keep his mind off of the claustrophobia factor of the teeny set, which he would be in for hours.

To make James Franco's portrayal of Aron Ralston as accurate as possible, the real Ralston told director Danny Boyle to have Franco recite lyrics from the jam band Phish, Ralston's favorite band.

Aron Ralston broke into tears during a Q&A session at the Toronto International Film Festival, after an audience member asked his opinion on his portrayal on screen. Ralston said it was challenging after he was comforted by the actors beside him.

Cillian Murphy was Danny Boyle's first choice to play Ralston before James Franco was cast.

As of 2018, features James Franco's only Oscar nominated performance.

The cave paintings shown in the opening credits sequence are taken from The Great Gallery, a large rock panel of such paintings, at least 1500 years old, in Horseshoe Canyon, Utah. Blue John Canyon where Aron was trapped is a tributary to Horseshoe Canyon.

Shia LaBeouf was considered to play Aron Ralston.

Sebastian Stan was considered to play Aron.

127 hours is the length of uninterrupted activity from when Aron Ralston awoke on the day of his accident to when he is put under anesthesia during his rescue. It is equal to 5 days and 7 hours.

Aron Ralston wrote a biography about his ordeal.

Jena Malone auditioned for a role.

This film is the second film directed by Danny Boyle to contain a time denomination in the title - the first being 28 Days Later... (2002) (he also acted as producer on 28 Weeks Later (2007)).

Katie Featherston auditioned for the role of Kristi.

Aron Ralston became a motivational speaker. He was busy in November of 2011. Some of his activities included: On November 16, 2011, he was the final keynote speaker for the 2011 Financial & Insurance Conference Planners Annual Conference, in San Antonio, Texas. On November 28, he spoke at the Fayetteville Town Center at the University of Arkansas.

Treat Williams and Kate Burton play husband and wife in this film. They also played a married couple in the movie Barefoot (2014).

Lake Bell was considered to play a role.

James Franco and Kate Mara have both played comic book characters, Franco played Harry Osborn/New Goblin in Sam Raimi's Spider-Man trilogy while Kate played Susan Storm/Invisible Woman in 2015's Fantastic Four.

James Franco and Lizzy Chaplin also star in The Disaster Artist (2017) together. James Franco directed The Disaster Artist.

Although not mentioned in the film, it took 13 men, a winch, and a hydraulic jack to lift the boulder high enough to retrieve Aron's arm from the canyon.

It took roughly one hour for Aron to cut through his own arm.

In 2004 Aron Ralston went back to the scene of the accident with NBC News Anchor Tom Brokaw to scatter the ashes of his amputated arm over the boulder that had trapped him.

Multiple arms and arm interiors were created for the surgery sequence, with a day and a half scheduled at the end of the film's shoot to document the intricacies of the scene. After the first long "take" of the surgery scene, done in real time and lasting twenty minutes, Danny Boyle canceled the last day and a half of the shoot. He felt he had captured everything needed in that first take.

The amputation scene reportedly caused some audience members to receive medical assistance. Special effects designer Tony Gardner heavily worked on the scene with medical professionals in order to re-create Aron Ralston's perspective. The scene was done in one take.

Aron Ralston did indeed record himself hallucinating, examining his life, and drinking his own urine.

In the last scene, Aron Ralston's real-life friends and family are by the swimming pool.