Realizing that she wanted to have the real life Ruth Bader Ginsburg appear at the end of her film, director Mimi Leder wrote to the Supreme Justice and was delighted when she responded with a yes. Her appearance in the film took three takes (Ginsberg wouldn't allow any more).
Backers of the film insisted that Ruth Bader Ginsburg's husband, played in the film by Armie Hammer, should not appear so supportive and be more antagonistic towards his wife's success. Screenwriter Daniel Stiepleman refused to do this.
During the opening argument, Felicity Jones in the lead role pauses uncomfortably; the real Ruth Bader Ginsburg didn't hesitate during the opening argument.