Joseph Gordon-Levitt wrote the part specifically for Scarlett Johansson, and was really happy when Johansson agreed to star in the movie.
The sound effect used when Jon throws tissues into the garbage after watching porn is the same sound used when files are dragged to the "trash" utility on a Mac, the computer used by Jon.
Joseph Gordon-Levitt considered casting friend Channing Tatum as Don Jon, before taking the role himself.
The Facebook page for Barbara Sugarman (Scarlett Johansson) is real, and her friends are celebrities under false names.
The original cut, which was screened at Sundance in 2013, was given an NC-17 rating by the MPAA. Writer and Director Joseph Gordon-Levitt cut some graphic porn footage that his character is watching throughout the movie from the final cut, which received an R rating. He chose to cut some of this footage, since he didn't want people to think this movie was solely about porn after being confronted with sexually graphic footage.
The film's original title, as advertised when it was shown at the Sundance and Berlin film festivals, was "Don Jon's Addiction". Joseph Gordon-Levitt subsequently decided to change it, because he felt that title put too much emphasis on the pornography storyline.
Joseph Gordon-Levitt and Tony Danza appeared in Disney's Angels in the Outfield (1994), when Levitt was only twelve years old.
Despite appearing in several scenes, Brie Larson has only one line in one scene.
Joseph Gordon-Levitt's theatrical directorial debut.
Channing Tatum, Anne Hathaway, Meagan Good, and Cuba Gooding, Jr. all appear in cameo roles as the actors and actresses in the romantic comedies Barbara (Scarlett Johansson) loves.
Emily Blunt and John Krasinski appear in a fake movie poster during the movie theater scene.
The Carl's, Jr./Hardee's commercial featured prominently in the film, was a real ad that premiered during Super Bowl XLVII starring Danish model Nina Agdal.
One of the posters at the theater features a still image of Russell Crowe from Gladiator (2000). It advertises the fictional movie "Holy Blood - Battle For Glory".
Some of the club-goers in the film are members of Joseph Gordon-Levitt's production company, HitRecord.
Joseph Gordon-Levitt claims on the Howard Stern Show to have come up with the idea of Don Jon while high on marijuana.
When the poster of "Special Someone" can be seen a second time it does not show Anne Hathaway and Channing Tatum anymore. A modified poster of The Lucky One (2012) featuring Zac Efron and Taylor Schilling is used instead.
Joseph Gordon-Levitt is good friends with his Havoc (2005) co-stars Channing Tatum and Anne Hathaway, who make cameos in this film as a couple in a romantic comedy that Don and Barbara (Scarlett Johansson) go see. He is also good friends with his Looper (2012) co-star Emily Blunt, who can been seen, alongside her husband John Krasinski, in a movie poster in the movie theater scene. He is also good friends with his Inception (2010) co-star Leonardo DiCaprio, who you can see on the poster to Titanic (1997) in Barbara's old bedroom.
The opening montage features visual clips, though no sound, from Benny Benassi's music video, "Satisfaction."
This is Julianne Moore's second film dealing with the subject of porn. She portrays a porn star in Boogie Nights (1997).
In one of Jon's porn videos, the blonde standing in front of the refrigerator, is porn star Kayden Kross.
The only time you see Jon's sister is at the dining table and church with the family present. In those places too, she's always on the phone. Not until up to one hour 17 minutes into the film does she speak. That's also a small dialogue.
