Harry Patterson Smith enlisted from Richmond where he was employed as a commercial traveller. He was 24 years old, single and had been born in Ballarat East. He enlisted on 17th August 1914 and was allocated to the 6th Infantry Battalion. The 6th Battalion drew its recruits from Melbourne and the northern suburbs. This area included Collingwood, Kew, Preston, Heidelberg and Carlton. The 6th Battalion, along with the 5th, 7th and 8th Infantry Battalions formed the 2nd Infantry Brigade, and were part of the 1st Australian Division.

During the initial training at Broadmeadows Private Smith was promoted Corporal on the 19th August 1914. Later, on the 1st of September, he was promoted Sergeant. He was obviously a very capable junior leader. Sergeant Smith was wounded in action at Gallipoli on the 8th May 1915, and was evacuated to Alexandria, Egypt. He had a gunshot wound in his left side.. On the 9th of May, whilst being evacuated, he was promoted again and appointed Second Lieutenant. He was admitted to Sty Andrew's Military Hospital, Malta , and later was transferred to The Officers' Convalescent Hospital at Draganara . He re-joined his unit on Gallipoli on 19th November 1915. The 6th Battalion remained in location near Bullecourt until they were relocated to Belgium to join in the great offensive launched to the east of Ypres. Lieutenant Smith was promoted to captain on 12th June 1917.

Unfortunately Captain Harry Smith received a gun shot wound to his chest on the 10th August 1918,. He took no further part in the fighting., and was evacuated to the 3rd London General Hospital in the suburb of Wandsworth. He was transferred to the 6th Australian Auxiliary Hospital on the 10th September 1918. He was reported convalescent on 8th October 1918, and then he was examined by a Medical Board on 21st November 1918 and declared to be 'fit for Home Service only'. Tree No. 43, an elm, was planted in the Ballarat Avenue of Honour by Miss R. Knipe., a Lucas 'Girl' on 4th June 1917.