He served in World War I as Brigadier-General on the General Staff of the Indian Corps from 1914, then was appointed General Officer Commanding 8th Division on the Western Front from 31 July 1915 (in which capacity he led the attack on Ovillers losing 5,400 men) until 8 December 1916 and was appointed Adjutant General, India from 5 Feb 1917 until 30 October 1920. Following the Amritsar massacre in 1919 it fell to Hudson, in his capacity as Adjutant-General, to tell Brigadier Reginald Dyer that he was relieved of his command. He went on to be General Officer Commanding-in-Chief, the Eastern Army in India on 1 November 1920 before retiring in 1924.