Joan Cusack (Then)
As the principal of Horace Green Prep School, Rosalie Mullins is very uptight and upholds the rules. However, it’s revealed during an outing with Dewey that Mullins used to be a wild child in her youth and is a huge fan of Stevie Nicks. Before her days as a principal, Joan Cusack was on “Saturday Night Live” and appeared as Debbie in “Addams Family Values.”