On 29 August 1942, during the Battle of Isurava, Kingsbury was one of the few survivors of a platoon that had been overrun by the Japanese. He immediately volunteered to join a different platoon, which had been ordered to counter-attack. Rushing forward and firing his Bren gun from the hip, he cleared a path through the enemy and inflicted several casualties. Kingsbury was then shot by a sniper and killed instantly. His actions, which delayed the Japanese long enough for the Australians to fortify their positions, were instrumental in saving his battalion's headquarters and he was posthumously awarded the Victoria Cross as a result.