It was initially formed in 1915 for service during the First World War and consisted of four infantry battalions—the 17th, 18th, 19th and 20th Battalions.
The majority of its personnel were drawn from men that had previously served in New Guinea with the Australian Naval and Military Expeditionary Force.
It served at Gallipoli, where it took part in the August Offensive before being evacuated in December 1915. In early 1916, the brigade was sent to France where for the next two and a half years it fought on the Western Front.
There were five Victoria Crosses awarded to members of the 5 Bde during World War One;
• Private W. Jackson 17th Battalion, 25-26 Jun 1916, at Bois Grenier, France.
• Sergeant C. Castleton 5th Machine Gun Company, 28 July 1916, at Pozieres, France
• Lieutenant P.V Storkey 19th Battalion, 7 Apr 1918, at Bois de Hangard, France.
• Corporal W.E Brown DCM, 20th Battalion, 6 Jul 1918, at Villers-Bretonneux France.
• LT J. Maxwell DCM, MC & Bar, 18th Battalion, 3 Oct 1918, at Beaurevoir, France.
Following the end of the war, 5 Bde was disbanded; however, it was re-raised in 1921 as part of the Citizens Military Force (CMF). At this time it consisted of the 4th, 20th, 36th and 54th Battalions.
During the Second World War the brigade was reduced to three infantry battalions—the 44th, 54th and 56th Battalions—and undertook defensive duties in Australia until it was disbanded in June 1944 as part of the reallocation of manpower resources undertaken by the Army at the time. In 1948 the CMF was established once more, albeit on a limited scale and 5 Bde was re-raised.
In 1960, with the introduction of the Pentropic Divisional Structure, the brigade ceased to exist as it was decided to move away from the traditional triangular formation.
The Pentropic structure was abandoned in 1965, however, and the Army returned to the previous tropical establishment.
The brigade was reformed at this time, albeit under the guise of the '5th Task Force', and consisted of three battalions—3rd Battalion, Royal New South Wales Regiment; 4th Battalion Royal New South Wales Regiment; and 17th Battalion, Royal New South Wales Regiment. In 1982 it reverted to the designation of '5th Brigade' and in 1987 all Reserve formations were reduced to two infantry battalions
The 5th Brigade currently consists of the following units:
• Headquarters 5th Brigade
• 1st/15th Royal New South Wales Lancers
• 23rd Regiment, Royal Australian Artillery
• 5th Combat Engineer Regiment
• 21st Construction Regiment
• 142nd Signals Squadron
• 1st/19th Battalion, Royal New South Wales Regiment
• 4th/3rd Battalion, Royal New South Wales Regiment
• 5th Combat Service Support Battalion
• Sydney University Regiment