Sugden was serving as the second-in-command of his battalion at the start of the First World War. He fought in the Second Battle of Ypres, and was wounded in September 1915. He returned to his regiment the following November. Sugden was awarded the Distinguished Service Order on 3 June 1916 and on 4 September 1916 he became Commanding Officer of the 4th Battalion DWR. On 17 December 1917 he was awarded a Bar to his DSO. He was promoted to brigadier-general on 7 June 1918 and took command of the 151st Infantry Brigade. The brigade was engaged in action in France between October 1918 and the Armistice of 11 November 1918.