Hare commanded 8th Brigade during the landing at Cape Helles and was subsequently wounded in the leg during the Gallipoli Campaign of the First World War. He was briefly acting General Officer Commanding 27th Division on the Macedonian front from December 1915. After that he became General Officer Commanding 54th (East Anglian) Infantry Division in April 1916 and commanded the division in Egypt and then in the First, Second and Third Battles of Gaza in 1917 and the Battle of Megiddo in September 1918 in Palestine. The division was demobilised in September 1919, but he continued to command it in its newly reconstituted form as a Territorial Army formation until he retired in July 1923.