Born in
Hanover in April 1891, Geisler joined the
Kaiserliche Marine (
Imperial German Navy) on 1 April 1909 as a
Seekadett, prior to
World War I and served during the entire conflict. He continued his career serving in the
Reichsmarine, the
Weimar Republic Navy, until joining the newly formed
Luftwaffe in September 1933. He ultimately reached the rank of
General der Flieger in July 1940. As commander of
X.Fliegerkorps from 2 October 1939 to 31 August 1942, he used his background as a sailor to specialise in anti-shipping aerial operations. He was awarded the
Knight's Cross of the Iron Cross on 4 May 1940. He retired in October 1942 and died on 25 June 1966 in
Freiburg im Breisgau. == Promotions ==