 He returned to Hull in 1901 at the request of Charles and Arthur Wilson to become Managing Director at Thomas Wilson Sons & Co. until its sale to Ellerman Lines in 1916 where he continued as Managing director of the combined Ellerman Wilson Line until he died.During the First World War Sanderson was appointed honorary colonel of the 2nd Northumbrian Brigade, Royal Field Artillery on 8 August 1914.On 1 September 1916, he was appointed a temporary major in the 1st Volunteer Battalion, East Yorkshire Regiment, and became honorary commandant of the regiment, as an honorary lieutenant-colonel, on 1 September 1918.