Director Gus Van Sant originally planned to make this movie in the 1990s, with Robin Williams starring as John Callahan.

Rooney Mara and Joaquin Phoenix have worked together in Her (2013), Mary Magdalene (2018) and Don't worry, He won't get far on foot (2018). They started dating during the production of Mary Magdalene in 2016.

-It is based upon the memoir of the same name by John Callahan.

Gus Van Sant has also directed Joaquin Phoenix's brother River Phoenix in "My Own Private Idaho"(1991).

-The film had its world premiere at the Sundance Film Festival on January 19, 2018.

Director Gus Van Sant makes a cameo in the film as an editor at Willamette Week. His face is only partially shown.

Jonah Hill was also named Donnie in The Wolf of Wall Street (2013).

In one scene, Jack Black mentions Orange County,CA. Jack Black starred in the movie Orange County.

Jonah Hill calls his Higher Power Chucky, after the doll in the movie Child's Play, however Child's Play wasn't released until 1988, and this movie is set before that.

The actor Udo Kier has also been in Gus Van Sant's film My Own Private Idaho; his character's name was also called Hans.