Eric Giles Miller was born on 2 March 1889 at Robe, South Australia to Alexander and Grace Miller. He had an older brother named Barton Bryce and a younger sister named Vera. Miller was a fitter by trade, fitting and assembling metal parts for machines and, particularly, locomotive engines. He also gained two years of militia experience. On 21 June 1912, Eric Giles Miller married Ruby May Wasley at Broken Hill, and they lived in Broken Hill for a short time before moving to Adelaide. They had two children- a daughter named Doris Marjorie, and another child whose name is unknown.
On 19 August 1914, at the age of 25, Eric Giles Miller enlisted for the Australian Imperial force. He was soon appointed to the 3rd Light Horse Regiment and embarked from Adelaide on 22 August 1914 aboard HMAT Port Lincoln. After undergoing training, Miller joined the Mediterranean Expeditionary Force in Gallipoli on 9 May 1915. He had several close calls in the trenches, and in September 1915, Miller became ill with enteric fever. He was sent to hospitals in Malta and England for his recovery. Upon his return to health, Eric Giles Miller was sent to France on 25 November 1916 as part of the 3rd Division Mounted Military Police. He was later transferred to the ANZAC Provost Corps on 9 February 1917, and then to the 43rd Battalion on 13 September 1917. Miller served with the 43rd Battalion for many months and saw plenty of action. He was part of the Battle of Hamel on 4 July 1918, and received gunshot wounds in the shoulder, back, thigh and neck. At the end of the war, Miller returned to Australia and arrived back in Adelaide on 28 March 1919.
Upon coming home, Eric Giles Miller lived in Adelaide and continued his trade as a locomotive engine fitter. During the Second World War, he was also part of the 2nd Battalion Volunteer Defence Corps. On 5 November 1950, Eric Giles Miller suddenly, of natural causes, at the age of 61. He was buried in Renmark Cemetery.