At this time, the brigade's constituent units were located across south-east Queensland and northern New South Wales including Brisbane, Ipswich, Toowoomba, Warwick, Lismore, Casino and Grafton.

[7] The 3rd Brigade was re-formed in August 1914, as part of the Australian Imperial Force (AIF) which was raised for service overseas during World War I.

[9] After being deployed to Egypt where they undertook further training, the brigade was committed to the fighting in the Gallipoli campaign, being the first Australian unit to land at Anzac Cove on 25 April 1915.

They subsequently remained on the peninsula until the end of the campaign in December 1915, taking part in a number of battles including the landing at Suvla Bay and the fighting at Lone Pine and Sari Bair.

During this time the AIF was expanded by raising new infantry battalions from cadre personnel drawn from experienced units and bringing in newly trained recruits from Australia.

[12] On 23 July 1916, the brigade took part in its first major battle when it was committed to the fighting on the Somme at Pozières, where the Australian 1st Division advanced 1,000 yards (910 m), capturing the village.

[13] In December 1916, Sinclair-MacLagan handed over command to Brigadier General Gordon Bennett, who led the brigade for the rest of the war.

[2] Later, throughout 1917 and 1918 battles were fought Bullecourt, Ypres, Menin Road, Passchendale, Hazebrouck, Amiens and along the Hindenburg Line before the fighting came to an end in November 1918.

[15] Initially this was undertaken in small blocks of continuous training, however, following Japan's entry into the war following the bombing of Pearl Harbor and the invasion of Malaya in December 1941, the 3rd Brigade was mobilised for wartime service.

[19] In March 1943, as the threat of invasion diminished, the brigade was re-allocated to the 4th Division[18] and was withdrawn to Adelaide, before moving to Queensland in July 1944.

The brigade subsequently became a direct command unit of the First Army, and was bolstered with the 6th Field Regiment and the 1st Independent Light Horse Squadron.

[23] In 1967, however, the brigade was returned to the order of battle, albeit under the guise of the 3rd Task Force, as part of the expansion of the Australian Army during the Vietnam War.

[28] The brigade is currently a combined arms formation and it fulfils the role of the Australian Army's ready deployment force on rotation.