Grand Army is based on a play by Katie Cappiello, who also serves as the showrunner on the TV version. As it turns out, Jean has a history with the writer in the theatre world! They met when Jean was just 16 years old and working with the nonprofit Opening Act, which works on arts programs in underfunded schools. According to WWD, Jean worked with Cappiello on several plays about social justice, including performances at the United Nations!