Zenker joined the Admiralty Staff in 1917. He was appointed to the North Sea area command in 1918, holding this post when the German war effort collapsed in November 1918.
After the war, he was an officer of the Reichsmarine, serving as Inspekteur der Marineartillerie from 1920 to 1923 and the top post of Chef der Marineleitung (Chief of the Naval Command) from October 1, 1924, to September 30, 1928. His tenure as head of the Reichsmarine saw the beginning of the rebuilding of the German fleet with the construction of light cruisers and torpedo boats and the planning of Deutschland class ships, later built as the Deutschland, Admiral Scheer, and Admiral Graf Spee.
Bradley, Dermot; Hildebrand, Hans H.; Henriot, Ernest (1990). Deutschlands Admirale 1849–1945. Die militärischen Werdegänge der See-, Ingenieur-, Sanitäts-, Waffen- und Verwaltungsoffiziere im Admiralsrang. Band 3: P–Z. Osnabrück, Germany: Biblio Verlag. ISBN3-7648-1700-3.
