[1] After attending school in Hanover and receiving his abitur, Zimmermann entered the Imperial German Army and fought in the First World War, earning the Iron Cross, 1st and 2nd class.

That spring, Zimmermann was appointed the North Westphalia District Leader of the newly created Reich Labor Service (Reichsarbeitsdienst) and held this position until June 1936.

[7] From 1 October 1937 through 30 June 1938, Zimmermann was the Chief of Staff (Stabschef) of SS-Oberabschnitt (Main Section) "Elbe," headquartered in Dresden.

He was also involved in planning for the future occupation of Azerbaijan, and the exploitation of its rich oil resources which were to be used in the German war effort.

From mid-February 1943 he was posted to the office of SS-Obergruppenführer Erich von dem Bach-Zelewski, the Higher SS and Police Leader (HSSPF) Russland-Mitte (Central Russia) in Mogilev.

He remained in Nikolajew until 10 October 1943 and then was transferred to become an SSPF for special duties on the staff of SS-Obergruppenführer Hans-Adolf Prützmann, the Supreme SS and Police Leader (HöSSPF) in Russland-Süd (Southern Russia).

In 1952, he joined the so-called Naumann Circle, a group of former Nazis who attempted to infiltrate West Germany's Free Democratic Party.