The 33rd Battalion was formed in January 1916 at a camp established at the Armidale showground in New South Wales. The bulk of the battalion's recruits were drawn from the New England region and thus it was dubbed "New England's Own". The Battalion's first, and only, commanding officer was Lieutenant Colonel Leslie Morshead, who would become famous as the commander of the 9th Australian Divisionduring the Second World War.

33rd Battalion marching through Armidale 1916 Armidale Camp 1916

The 33rd Battalion became part of the 9th Brigade of the 3rd Australian Division. It left Sydney, bound for the United Kingdom in May 1916. Arriving there in early July, the battalion spent the next four months training. It crossed to France in late November, and moved into the trenches of the Western Front for the first time on 27 November, just in time for the onset of the terrible winter of 1916-17.

The Battalion had to wait until the emphasis of British and Dominion operations switched to the Ypres Sector of Belgium in mid-1917 to take part in its first major battle; this was the battle of Messines, launched on 7 June. The battalion held the ground captured during the battle for several days afterwards and was subjected to intense artillery bombardment. One soldier wrote that holding the line at Messines was far worse than taking it. The battalion's next major battle was around Passchendaele on 12 October. The battlefield, though, had been deluged with rain, and thick mud tugged at the advancing troops and fouled their weapons. The battle ended in a disastrous defeat.

A group of Australian soldiers quartered at one of the old German reinforced concrete pillboxes, known as 'Kit and Kat', near Zonnebeke.

For the next five months the 33rd alternated between periods of rest, training, labouring, and service in the line. When the German Army launched its last great offensive in the spring of 1918, the Battalion was part of the force deployed to defend the approaches to Amiens around Villers-Bretonneux. It took part in a counter-attack at Hangard Wood on 30 March, and helped to defeat a major drive on Villers-Bretonneux on 4 April.

Later in 1918, the 33rd also played a role in the Allies' own offensive. It fought at the battle of Amiens on 8 August, during the rapid advance that followed, and in the operation that breached the Hindenburg Line at the end of September, thus sealing Germany's defeat. The 33rd Battalion disbanded in May 1919.