During a panel discussion at Deadline’s Contenders Television, Helen Mirren revealed that she and Harrison Ford were cast in the Paramount+ series "1923" without having seen a script. Creator Taylor Sheridan prefers to write characters tailored to his chosen actors. Mirren suggested meeting with Sheridan before accepting the role, which was a success.

Aminah Nieves and Brandon Sklenar also spoke about their casting experiences, with Nieves feeling compelled to honor her community and Sklenar receiving a call while camping and subsequently testing for the role in Jackson Hole. Mirren added an Irish accent to her character, feeling that Westerns lacked accurate representation of recent immigrants' accents.