One of four sons, Allan Boase was educated at Brisbane Grammar School and in 1911 entered the Royal Military College, Duntroon, in the Federal Capital Territory, from which he was commissioned in 1914 as part of the first class of cadets who were graduated early due to the outbreak of the First World War.

[1][2] Joining the 9th Battalion, Australian Imperial Force, in August 1914, he was shipped to Egypt the following month after the outbreak of the First World War.

Promoted to major at the end of the year, Boase performed staff duties for the remainder of the war[1] within the headquarters of a number of brigades and the 5th Division.

Dispatched with the division to the Middle East in late 1940, he was promoted to temporary brigadier in late November[3] and made responsible for the Base and Lines of Communication Units around Gaza,[4] where the 2nd AIF had established its base.

[1][7] After the war, Boase was the Australian Army and defence representative in London until a temporary promotion to lieutenant general in March 1949.