Between the wars, Bennett pursued a successful business career and also rose from colonel to major general in the Australian citizen armed forces. He resented and publicly criticized both permanent regular army officers and British military representatives. Bennett particularly disliked Sir Thomas Blamey, who headed the World War II Australian Infantry Force, occupying a position Bennett coveted.
Despite his seniority, Bennett received no command until September 1940, when he headed the Australian 8th Division. In September 1941, he accompanied his force to Singapore, where his relations with his juniors and with British military officers were predictably inharmonious. When the Japanese invaded in January 1942, Bennett commanded "Westforce" on the peninsula and had some initial successes against the Japanese troops. Withdrawing to Singapore Island, he commanded the Western Area, which bore the brunt of the main Japanese assault on 8 February. After five days of fierce fighting, Bennett and others advised Lieutenant General Sir Arthur Ernest Percival, the British commander, to surrender. When negotiations began, Bennett handed over command of his force to a subordinate, and with other Australian officers, he fled by sampan from Singapore, reaching Melbourne on 2 March.
Bennett received a mixed reception. He was promoted and became commander of III Corps in Perth, but Blamey ensured he received no further field command, and in May 1944, Bennett gave up active duty. Seeking to exonerate himself, he published a highly apologist book stating his case, an effort undercut when General Percival was released by the Japanese at the end of the war in August 1945 and wrote to Blamey condemning Bennett's actions as desertion of his men. A military court of inquiry ruled against Bennett, although a civilian commission exonerated him, a decision that was generally considered politically motivated. In retirement, Bennett cultivated an orchard farm and wrote extensively on military topics. He died at Dural, New South Wales, on 1 August 1962.
Bennett, Henry. Why Singapore Fell. London: Angus and Robertson, 1944.; Keogh, E. G. The South West Pacific, 1941–45. Melbourne, Australia: Grayflower Productions, 1965.; Legg, Frank. The Gordon Bennett Story. Sydney, Australia: Angus and Robertson, 1965.; Lodge, A. B. The Fall of General Gordon Bennett. Boston: Allen and Unwin, 1986.; Wigmore, Lionel. The Japanese Thrust. Canberra: Australian War Memorial, 1957.