Although its numerical name was designated during the First World War, the 1st Battalion can trace its lineage back to 1854, when a unit of the Volunteer Rifles was raised in Sydney.

[1][2] Following that the unit went through a number of changes in composition and designation as the various colonial defence forces were reorganised during the mid to late 19th Century.

[1] In 1885, the 1st Regiment provided a detachment of one officer and 75 men to serve in Sudan during the Mahdist War, for which they received the battle honour "Suakin 1885".

Up to 100 men from the pre-war 1st Infantry Regiment are believed to have served in various AIF units during the war, including the 1st Battalion.

[7] After undertaking further training and serving in a static defence role around the Suez Canal, the battalion took part in the Landing at Anzac Cove, coming ashore with the second and third waves on 25 April 1915.

The Turks counterattacked almost immediately and for the course of the next three days the fighting continued, during which time two members of the battalion, Alfred Shout and Leonard Keysor, performed acts of valour for which they were later awarded the Victoria Cross.

In early 1916, the AIF's infantry divisions were sent to France where over the course of the next two-and-a-half years they would take part in the fighting against the Germans on the Western Front.

[7] On 21 September all but one member of "D" Company refused to take part in an attack as a protest against the battalion being sent back into combat when it had been about to be relieved.

Following the end of hostilities, the process of demobilisation began and slowly the battalion's numbers dwindled as its personnel were repatriated to Australia.

[3] A further review of defence requirements was carried out in 1920, after which it was determined that the Militia should be further reorganised to perpetuate the battle honours and designations of the AIF.

[3][4] In 1929, following the election of the Scullin Labor government, the compulsory training scheme was abolished and in its place a new system was introduced whereby the Citizens Forces would be maintained on a part-time, voluntary basis only.

[3][17] With the outbreak of the Second World War once again the government made the decision to form an overseas expeditionary force outside of the pre-existing Militia units.

[18] To maintain the ability of the Army to defend Australia should Japan enter the war, it was decided once again to limit the number of militiamen that were allowed to enlist in the Second Australian Imperial Force (2nd AIF) to roughly one quarter.

[19] While the units of the 2nd AIF were sent overseas to England, North Africa and the Middle East, the militia remained in Australia to carry out various garrison duties and training to improve the nation's overall readiness.

Following Japan's entry into the war in December 1941 this changed and over the course of 1942–45 many Militia units were mobilised and deployed to fight in New Guinea, New Britain, Bougainville and Borneo.

As a result of this, and the serious manpower shortages experienced by the Australian economy from October 1942 onwards eight Militia battalions were disbanded while another eleven more were broken up and their personnel distributed to other units.