During his military career he achieved fame and notoriety for his mixture of heroic exploits and explosive temperament. He was awarded the Distinguished Service Order for his exploits in Gallipoli in February 1916 and on 1 January 1917 was awarded the Companion of St Michael and St George (CMG). During the summer and autumn of 1917 he commanded 1st Battalion, the Royal Inniskilling Fusiliers and was instrumental in the early success achieved during the Battle of Cambrai on 20 November for which he received the Victoria Cross from King George V at Buckingham Palace on 23 January 1918. Kelly was gassed and wounded at various times.