Duncan McPhedran joined the City of Glasgow Police in 1912 after service with the Argyll and Sutherland Highlanders.
He served with the Glasgow Police until 1914 when he joined the Scots Guards at the outbreak of the First World War. He rose to the rank of Sergeant and was wounded while serving with them in the Battle of the Somme in 1916. In 1917 he was commissioned as 2nd. Lieutenant in the King’s Own Scottish Borderers and was severely wounded in Belgium in 1918. Between 1919 and 1920, he served as a Company Commander in the Army of Occupation in Germany, having been promoted to Lieutenant and Acting Captain.
On demobilisation in 1920, he re-joined the City of Glasgow Police and in 1922 he was appointed to the Recruits Training School as educational and assistant drill instructor. He was promoted to Sergeant in 1924 and in 1928 was promoted Inspector and transferred to the ‘A’ (Central) Division.
In 1933, he was promoted to Lieutenant and second in command of the ‘A’ (Central) Division and in 1938 he was promoted to Superintendent in charge of the ‘C’ (Eastern) Division, the roughest part of the City.
In 1945, Superintendent McPhedran was awarded the King’s Police Medal for Distinguished Service.