It was formed in February 1943 to provide armoured support for infantry units operating in the South West Pacific Area.

Its composition varied over time, but usually comprised several armoured regiments equipped with Matilda II or M3 Grant tanks as well as some support units.

The brigade's main role throughout its existence was to provide a pool of armoured units and sub-units that could be deployed to augment infantry forces.

As there was no longer any threat of Japanese forces invading Australia, the 2nd Armoured Division was disbanded to free up manpower for other purposes.

[3] As it was not practical or necessary to deploy large armoured units in the jungle terrain common across the South West Pacific, the brigade was organised into several self-supporting regimental groups.

These regimental groups could in turn provide sub-units with the necessary logistics support to form the armoured component of other units during combat operations.

[12][13] Also in October 1943, a party from the 4th Armoured Brigade armed with pistols was sent to Grovely Camp near Brisbane to put down a riot by soldiers being held under detention there, but did not need to use force.

[17] During June it also established a training area at Nerang in Queensland, where armoured units could practice operating in tropical conditions.

This squadron was to operate troop-carrying Landing Vehicles Tracked, but they did not arrive in time for the unit to see action before the end of the war.

[21] In January 1945 the 2/6th Armoured Regiment was transferred to the direct control of Land Headquarters, and moved to Puckapunyal in Victoria the next month.

[15][23] One of the 4th Armoured Brigade's regimental groups supported Australian Army offensive operations in New Guinea and Bougainville during 1944 and 1945.

The remainder of this regiment subsequently supported the 9th Division during the early stages of the Battle of North Borneo from 10 June.

[3] Macarthur-Onslow played an important role in guiding these processes, including by helping his subordinates to overcome institutional barriers.

[31] The 4th Armoured Brigade also trialled modifications to the Matilda II and Grant that sought to waterproof the tanks so they could travel through rivers and coastal waters.

[40][41] Only the 1st Armoured Regiment remained an active unit, and returned to its pre-war designation of the 1st Royal New South Wales Lancers in 1949.