After the war Ritter became a designer before working in public relations in the film industry. In 1932 he was appointed Director and Production Manager for the UFA film company. Ritter, a member of the National Socialist German Workers Party (NSDAP), attempted to make films that supported the fascist ideology.
In his films Ritter glorified Germany's military past and during the Second World War he made eight films about the Luftwaffe. His best known films include Urlaub auf Ehrenwort (1937), Patrioten (1937), Pour le Merite (1938), Legion Condor (1939), Uber alles in der Welt (1941) and Stukas (1941).
After the war Ritter emigrated to Argentina, where he was head of Eros-Film Mendoza. He returned to Germany in 1954 where he formed his own film company, Karl Ritter-Filmproduktion. Karl Ritter died on 7th April, 1977.