George Duncan Shaw was born in Melbourne during 1894. Prior to the First World War he was a mechanical engineer and gained military experience through his engagement with the Citizen Military Forces, as a lance sergeant in the 86th Battalion. In 1914 Shaw attempted to enlist in the Australian Imperial Force, but could not gain the consent of his parents, forcing him to wait until he was 21. On 10 May 1915 Shaw joined the 28th Infantry Battalion as a second lieutenant, training at Blackboy Camp until departing Fremantle aboard the HMAT Ascanius on 29 June 1915.

At Gallipoli, Shaw was involved in the evacuation in December, remaining behind with a number of men at Russell's Top to support the retreat. After a short period in Egypt, Shaw was transferred to 2nd Pioneer Battalion in France and by the end of 1916 was promoted to captain. Shaw was Mentioned-in-Despatches by Sir Douglas Haig on 9 April 1917 and was gassed at the battle of Bullecourt in May 1917. On 20 September 1917 Captain Shaw took charge of a party proceeding with road works around Ypres, the party came under intense shelling and suffered a number of casualties. Shaw evacuated the wounded before motivating the remaining members of the party to complete the road works. For this action Shaw was awarded the Military Cross.

In mid-1918 Shaw was wounded and eventually invalided to Wandsworth Hospital, returning to Australia in December of that year. After the war George Shaw returned to 86th Battalion and then enlisted in the Second World War.