Jessica Chastain said she initially had the impression that Tammy Faye Bakker often had running mascara, as parodies and impressions of Tammy Faye on late night TV and Saturday Night Live (1975) often featured her crying with heavily running mascara. Chastain noted that when researching Tammy Faye, she couldn't find a single image or video of her with mascara running; Tammy Faye only wore waterproof mascara.
The film had been Jessica Chastain's passion project for a number of years before it ended up being made. She had seen the documentary The Eyes of Tammy Faye (2000) around 2012 and felt drawn to tell Tammy Faye Bakker's story after acquiring the rights to produce a biopic about the infamous televangelist.
This is the second screen version of the Jim & Tammy Faye Bakker story. The first was a 1990 made for TV movie starring Kevin Spacey and Bernadette Peters, titled Fall from Grace (1990).
At 5'4", Jessica Chastain is the same height as the real life Jim Bakker (Andrew Garfield, who plays Bakker, is 5'10"). Tammy Faye Bakker was 4'11".