The 2nd Battalion was raised at Randwick, New South Wales, in August 1914 as part of the Australian Imperial Force (AIF), which was formed from volunteers for overseas service shortly after the outbreak of the First World War.

[7][8] The battalion's first commanding officer was Lieutenant Colonel George Braund,[6] a citizen soldier and Member of Parliament in the New South Wales Legislative Assembly, who held the seat of Armidale.

[19] One of the 2nd Battalion's platoons, under Lieutenant Leslie Morshead, advanced further than any other Australian unit, making it to the slopes of Baby 700, before a determined counter-attack by Ottoman forces drove them back in the afternoon.

In the early afternoon, Braund led them up the steep terrain under fire to the vital junction between two positions known as "Walker's Ridge" and "Russell's Top".

At around midnight on the night of 3/4 May, the 2nd Battalion's commanding officer, Braund, who was partially deaf, was accidentally killed as he attempted to visit 1st Brigade headquarters after failing to hear a challenge from a sentry, who shot him believing that he was an enemy soldier.

[6] Following the initial establishment of the beachhead, the campaign moved into a second phase as the Australians began work to consolidate and slowly expand their position around the lodgement.

This began late on 18 May with the heaviest artillery bombardment of the campaign to that point, during which the 2nd Battalion's orderly room, located on "MacLaurin's Hill", was hit.

[26] With only limited machine-guns and with bad light hindering the supporting artillery, the job of turning back the Turkish assault fell to the riflemen and by maintaining strict fire discipline, great effect was achieved.

Ultimately, the August Offensive, of which the fighting at Lone Pine had been a part, failed to deliver the Sari Bair heights to the British Empire forces and their allies,[36] nor did it break the deadlock.

[38] In the intervening months, some personnel had been shifted away from Gallipoli as other the situation in other theatres became more relevant, and in late November, Lord Kitchener toured the peninsula.

[39] The evacuation, which has been described as "more brilliantly conducted ... than any other phase of the campaign",[40] took place in stages, and with the maintenance of secrecy a key consideration, a series of "ruses" were used to conceal the withdrawal.

[41] A small element from the 2nd Battalion was among the last Australian troops to leave, with a group of 64 men remaining in possession of the "Black Hand" position until 2:50 am on the final morning.

The 2nd Division had been formed in July 1915, and part of this had been dispatched to Gallipoli in the later stages of the campaign, but the large increase in volunteers in Australia meant that further plans for expansion could take place.

[50] Shortly afterwards, on 7 April, the units of I Anzac Corps were assigned to a "quiet" sector of the line near Armentières to gain experience of trench warfare.

"[53] In June, during a brief period away from the line in billets, the battalion, along with the rest of the 1st Brigade, was reviewed by the Australian prime minister, Billy Hughes near Fleurbaix.

[35][65] After this, they were sent to Pernois for rest and re-organisation,[66] and after being brought back up to about two-thirds strength,[67] the 2nd Battalion's next involvement in the fighting came around Mouquet Farm when they were briefly put into the line on 18/19 August to provide reinforcement, before being quickly relieved a few days later.

[75] Winter began to set in at this point, and even though combat operations all but ceased during this time, the battalion endured considerable hardships amid snow and rain, in a sector that has been described as "the worst ... of the sodden front".

[79] Falling back up to 31 miles (50 km) in some places, they took up positions along a series of heavily fortified, purpose-built strong-points which the Allies subsequently named the "Hindenburg Line", which, due to the reduced frontage, enabled them to free up some 13 divisions of reserves.

Sergeant Thomas Brew, no 714, was responsible for the reorganisation of the left-centre company and was recommended and subsequently awarded a Distinguished Conduct Medal (DCM) for his actions.

Amongst this group was Private Bede Kenny who, under heavy fire, rushed the enemy position and destroyed it with grenades, taking the surviving Germans prisoner.

[95] As the Germans attempted to force the Australians back, the 2nd Battalion was moved around a number of times to shore up the line,[96] until units of the 5th Division came up to relieve those of the 1st Brigade on 8 May.

[97] The battalion's next major action came in mid-September when they were committed to the fighting around Menin Road, which formed part of the wider Third Battle of Ypres, in a supporting role.

They were subsequently relieved shortly afterwards on the night of 22/23 September by troops from the 14th Brigade,[100] as fresh divisions were brought up to continue the attack at Polygon Wood.

[104] The attack went in on 4 October, and after overcoming an encounter with a German infantry regiment, the 212th, in no man's land, the Australians successfully managed to capture their objectives.

[107] On 19 December 1917, after the battalion had moved to the relatively quiet Messines sector in Flanders along with the other Australian divisions following their involvement in the Passchendaele operations,[108] Stevens resumed command;[35] Milligan having been elevated to the general staff.

[121] Throughout June and July they alternated between Meteren and Merris during which time they continued to raiding operations, which advanced the line about 1,000 yards (910 m) without significant loss.

[6] In early October, the rest of the Australian Corps, severely depleted due to heavy casualties and falling enlistments in Australia, was also withdrawn upon a request made by Prime Minister Billy Hughes, to re-organise in preparation for further operations.

[141] In 1929, following the election of the Scullin Labor government, the compulsory training scheme was suspended altogether as it was decided to maintain the part-time military force on a volunteer-only basis.

[143] The end of compulsory training and the fiscal austerity that followed due to the economic downturn of the Great Depression meant that the manpower available to many Militia units at this time was limited and as a result their frontage dropped well below their authorised establishments.

[138][141] In 1961, the Pentropic 2 RNSWR was entrusted with the battle honours that had been awarded to the 2/2nd Battalion, which had been raised as part of the Second Australian Imperial Force and which had served in North Africa, Greece, Crete and New Guinea.