[citation needed] Shortly before the outbreak of the First World War Behncke was promoted to Konteradmiral (Rear Admiral) and again assigned to the general staff.

During the conflict he was opposed to Admiral Alfred von Tirpitz's theories on submarine warfare, and was appointed head of the III Battle Squadron, composed of eight of the nine most modern battleships of the German navy (the König and Kaiser classes).

Leading these ships aboard his flagship SMS König, Behncke took part in the Battle of Jutland, where he was seriously wounded by a shell splinter and found himself in command of the whole fleet during the third phase of the action.

[citation needed] During the 1917 Battle of Moon Sound he prevented the retreat of part of the Russian fleet and sank the Slava.

[citation needed] Behncke regained office after the war, replacing admiral Adolf von Trotha, and retired from the navy in 1924.