Alan qualified L.R.C.P., L.R.C.S. in 1904. He joined the Medical Services at the rank of Lieutenant on 31st July 1905. Between 12th January and 10th August 1908 he was reduced to half pay due to ill-health. He gained promotion to Captain on 29th August 1909, and from 1909 to 1913 served in South Africa. When war was declared Alan was stationed at Aldershot. He was posted to serve as the medical officer of the 1st Field Squadron, Royal Engineers, and entered the war with them in France. During the retreat from Mons, Alan was taken captive by the Germans at Ligny-en-Cambreans. From there he was taken to a POW camp in Torgau, Germany.
On 10th February 1915, German authorities stated they needed six medical officer to go to Wittenberg camp where medical treatment was urgently needed - Alan was one of the volunteers. When they arrived four of the officers were sent into the camp but Alan was taken to Elbarfin Hospital, and remained there until 7th March 1915, when he himself, and another R.A.M.C. officer (Maj Harold Priestley) entered Wittenberg Camp. The camp was riddled with typhus, and the four officers had now become infected. Harold immediately took command of the situation and placed Alan in charge of a surgical ward there. By July the camp was cleared of the epidemic. For his service during the typhus epidemic at Wittenberg Camp he was granted a Companion of the Order of St Michael and St George, and received a Gold Life Saving Medal of the Order of the Hospital of St John of Jerusalem. He was repatriated on 28th February 1916. Alan returned to France and Belgium, serving there from 1916 to 1918. On 28th February 1918 he was promoted to the rank of Major. From 1920-1921 and 1922 - 1923 he served in India. He was reduced to half pay on 21st October 1923 due to ill-heath, then on 22nd July 1925 retired with pay. Alan died in Yorkshire. He was the son of Francis Furse and Lucy Mary (nee Cunliffe); and the husband of Kathleen Margaret O’Donoghue.