Stanley had held a commission within the Medical Services from the 31st August 1903. Serving under the rank of Captain, and as Regimental Medical Officer attached to the 2nd Bn. Royal Irish Rifles, he entered the war in France on the 14th August 1914. Stanley was wounded and invalided home, but returned to the war in 1915 and served as Commanding Officer to the 53rd Field Ambulance. He was promoted to Major on the 28th February 1915, but served as temporary Lieutenant Colonel between 12th July 1915 to 7th May 1916. In 1918, Stanley was sent to serve in Italy with No 79 General Hospital and remained there until he was posted to India in 1919. He served in India until 1924, and continued to serve with the Medical Services until he retired on the 31st August 1932, at the rank of Lt/Col. Stanley died in Northfleet, Kent.