Doermer himself has also directed a fair number of films including documentaries and television films.
He starred in the 1966 film No Shooting Time for Foxes. The film was entered into the 16th Berlin International Film Festival, where it won the Silver Bear Extraordinary Jury Prize.
In 1962, he was one of the 26 authors of the famous Oberhausen Manifesto, demanding a change in German film.
In 1969, Doermer appeared as a German soldier attending the Christmas truce in Sir Richard Attenborough's satirical World War I musical film Oh! What a Lovely War.