William was the third of five sons born to Walter and Margaret Duncan at Inverell. He attended Inverell Public School and then served a five year apprenticeship to become an Engineer. With his Mother’s permission, at the age of eighteen, he enlisted in May 1915. He was a member of the Inverell Cadets at this time.
After joining the 20th Battalion, A Company he departed Australia on the ship HMAT A35 Berrima in June 1915 and spent several months in Egypt. In a letter published in the Glen Innes Examiner newspaper 27 September 1915, William wrote to his Mother saying ‘I have never for a moment been sorry that I joined the Army. And I am quite willing to give my life for my country and to uphold the fighting traditions of my family’.
During March 1916 William was sent to France and then reported missing in Action on 5 August. One year later a Court of Inquiry found that he had been Killed in Action at Pozieres, France. Private Duncan has no known grave and his name is recorded on the Australian National Memorial, Villers-Bretonneux, France. His few remaining personal effects, including razor, notebook, scarf, metal matchbox and letters, were returned to his Mother.
At Inverell William’s name is inscribed on the Cenotaph and Honor Roll. In 1919 a memorial tree was planted for him in Kurrajong Parade.
An older brother, Walter, also served in France and was awarded the Distinguished Service Order for his part in the Battle of Villers-Bretonneux in 1918.