The missing Bennington College student referred to in the film was Paula Jean Welden who, while off campus, disappeared on December 1, 1946 while walking on Vermont's Long Trail hiking route.
The film is set in about 1950, the year before Jackson's novel Hangsaman, which she is in the process of writing in the film, was published. Shirley had the first of her four children in 1945, but in the film no children are seen or referred to.
Elisabeth Moss' co-star in "The Invisible Man", Oliver Jackson-Cohen, and Victoria Pedretti in "Shirley" both starred as twins in the TV series "The Haunting of Hill House", an adaptation of a Shirley Jackson novel.
Victoria Pedretti was in The Haunting of Hill House (2018). She portrayed Nell. Shirley Jackson wrote the novel.
Elisabeth Moss portrays real-life author Shirley Jackson.