As its American "cousin" (both types having been derived from the NA-16) the T-6 did for many Allied Air Forces during WWII, the Wirraway served as one of the RAAF's main trainer types from 1939. The type made its last operational flight in 1959 after being gradually replaced by the new Winjeel trainer. Beside serving as a trainer aircraft they were also operated in combat roles, including as an emergency fighter. At the outbreak of the Pacific War in December 1941 Wirraways equipped seven RAAF squadrons: Nos 4, 5, 12, 22, 23, 24 and 25.
A group of five Wirraways based at Kluang in Malaya for training purposes was pressed into combat against Japanese ground invasion forces; these were generally flown by New Zealanders with Australian observers, and had some successes.
On 6 January 1942, Wirraways of No. 24 Squadron attempted to intercept Japanese seaplanes flying over New Britain; only one managed to engage an enemy aircraft, marking the first air-to-air combat between RAAF and Japanese forces. Two weeks later, eight 24 Squadron Wirraways defended the city of Rabaul from over 100 Japanese attacking bombers and fighters, resulting in the destruction or severe damage of all but two of the Australian aircraft. On 12 December that year, Pilot Officer J. S. Archer shot down a Japanese A6M Zero aircraft after he spotted it 1000 feet (about 300 metres) below him and dived on it, opening fire and sending the Zero hurtling into the sea. This was the only occasion that a Wirraway shot down another aircraft (and is one more than the total of aircraft shot down by its fighter offspring, the Boomerang). Fighter versions of the Wirraway operated over New Guinea for some time on ground attack and other Army co-operation tasks until other RAAF aircraft such as the Boomerang and American Curtiss P-40s were delivered to replace them.
Many front-line squadrons of the RAAF had at least one Wirraway attached to serve as a squadron 'hack', that is, an aircraft employed on errands such as visits to headquarters or other bases. At least one aircraft (formerly A20-527) flew as part of Headquarters Flight 5th Air Force in full United States Army Air Forces markings.