Joseph Gordon-Levitt wrote the part specifically for Scarlett Johansson, and was really happy when Johansson agreed to star in the movie.
PornHub, a real-life pornography video website Jon goes on, supplied videos for production.
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.
The Facebook page for Barbara Sugarman (Scarlett Johansson) is real, and her friends are celebrities under false names.
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.