 He fought in Mesopotamia in the First World War and was wounded during the siege of Kut-el-Amara.After Kut fell in April 1916 he was taken prisoner by the Turks.After the war Elton was elected a Fellow of Queen's College, Oxford in 1919, and was lecturer in modern history from 1919 to 1939, dean of the college between 1921 and 1923 and tutor from 1927 to 1934.