 He rejoined the regiment following the outbreak of the First World War in 1914, and served with the 1st Battalion, Grenadier Guards in France from 1914 until 1916.In 1915 he was appointed temporary lieutenant colonel in command of the 1st Battalion until 1916, when he was appointed brigadier general in command of Infantry Brigade, which appointment he held until June 1917.In October 1917, appointed brigadier general on the Imperial General Staff to command the British Military Mission (Training) to the US.