In April 1916, at the age of 19, Hall enlisted in the Australian Imperial Force (AIF). After training, he was posted to 54th Battalion, then serving on the Western Front in France. He was wounded in late March 1917, within two months of arriving in France. Back in the front lines by late April, he saw action during the Battle of Bullecourt and later, during the second phase of the Battle of Passchendaele, in the Battle of Polygon Wood. He was promoted to corporal after this latter battle.