Based on Laure de Clermont-Tonnerre's short film Rabbit (2014), about a female prisoner entrusted with the titular animal as part of a correctional facility's 'pet partnership' program.

In the movie The character Tom was playing by Thomas Smittle who participated in the actual program that the movie is based on. Thomas was in the program from 2019-2011 and had the top selling horse in the history of the program a red roan gelding that sold for $8500.00.

Laure de Clermont-Tonnerre's feature film directorial debut. She developed Mustang through the Sundance Labs and received the Sundance Institute/NHK Award for the project in 2015.

In one scene, Coleman's cellmate sarcastically refers to him as John Wayne. Bruce Dern, who appears in this film, appeared alongside Wayne in The Cowboys, murdering his character. It was one of Wayne's few on-screen deaths.