The initiative to establish the castle theater originated from Holk Freytag, who became the founding artistic director in 1975. Together with his ensemble, Freytag gained attention with his committed, experimental theater before moving on to the Wuppertaler Bühnen and then to the Staatsschauspiel Dresden.
Important performances include the ancient tragedies "The Bacchae" and "The Oresteia" as well as plays by Brecht and Büchner. The castle theater is still committed to its claim of political and social relevance and has further expanded this tradition with "Bringing the theater into the city and the city into the theater" as well as with dialogues between the podium and the audience in the "Moers Conversations."
With the fitting address "Kastell" and located in a vault, the castle theater Moers offers a maximum of 150 seats. But there are other performance venues: the theater hall, which was opened in 2004, as well as the chapel, studio, and powder house. In 2006, the theater was expanded to include an educational department with children, youth, and intergenerational theater projects. Additionally, the "Junge STM" hosts an annual children and youth theater festival: the "Penguin’s Days."