During World War II, the brigade was mobilised for defensive duties in December 1941, and assumed positions along the northern coast to defend against a possible invasion.

[1] These units were based in depots in the Hunter Valley and the northern part of the state including Armidale, Casino and West Maitland, with troops being drawn from the areas that had previously been assigned to the disbanded 2nd and 3rd Light Horse Brigades.

At this time, the brigade's headquarters was located at Armidale, and in the event of an invasion was tasked with defending positions along the northern coast, and preventing an enemy force from advancing inland towards the Central Tablelands.

This lasted until January 1942 when the brigade was re-oriented towards a flank defence role in support of the garrison covering Newcastle.

[4] It did not see any active service at this time and was converted into the 2nd Motor Brigade in March 1942,[1][5] as part of an effort to motorise or mechanise Australia's mounted forces in the early war years.

These formations were to be established on the light scale, to complement the 1st Armoured Division, which had been raised as part of the Second Australian Imperial Force.

The brigade did not see any active service and was disbanded at Gherang in April 1943, as part of a draw down of Australia's armoured forces that was undertaken once the threat of an invasion had passed.

[4] At this time, the Australian government decided to reallocate some of the manpower that had been tied up in the armoured divisions to other formations that would be used for jungle warfare, or to civilian industry.