 After 1945 he worked for the East German state film company DEFA and as a radio play author.He was one of the founding members of the Socialist Unity Party of Germany (SED), which became the dominant party in the German Democratic Republic (East Germany).In the early 1950s, Apitz worked as a guide to the former camp, Buchenwald, and was "actively involved in the plan for the earliest expedition to be shown there in 1952."