Albert Sidney Dunk was born at Morgan, South Australia on 5 May 1891 to parents Albert and Winifred Dunk. A station overseer by trade, he enlisted at Adelaide on 24 May 1916 with the 2nd Depot Battalion. On 16 January 1917 he departed Adelaide aboard HMAT Bulla with the 3rd Light Horse Regiment. He served with this unit in Egypt and Palestine. On 31 October 1917, at the Battle of Beersheba, Dunk sustained a gunshot wound to his right foot and was transferred shortly after to the 14th Australian General Hospital in Cairo. Albert Dunk returned to Australia on 20 July 1919.