Doran was in command of 8th Brigade when the First World War broke out in August 1914, and the British Expeditionary Force was mobilised for service. His younger brother, Walter Robert Butler Doran, also commanded a brigade of the Expeditionary Force; 17th Infantry Brigade in 6th Division. He took the brigade to France and commanded it through the Retreat from Mons, the Battle of the Marne and the First Battle of the Aisne. On 20 October, one of his battalions – the 2nd Royal Irish Regiment – was surrounded during the Battle of La Bassée and effectively destroyed for lack of support; on 23 October, he was relieved of command of 8th Brigade and sent home.