On 31 May 1940, following the outbreak of World War II, Gorton enlisted in the Royal Australian Air Force Reserve. At the age of 29, Gorton was considered too old for pilot training, but he re-applied in September after this rule was relaxed. Gorton was accepted and commissioned into the RAAF on 8 November 1940. He trained as a fighter pilot at Somers, Victoria and Wagga Wagga, New South Wales, before being sent to the UK. Gorton completed his training at RAF Heston and RAF Honiley, with No. 61 Operational Training Unit RAF, flying Supermarine Spitfires. He was disappointed when his first operational posting was No. 135 Squadron RAF, a Hawker Hurricane unit, as he considered the type greatly inferior to Spitfires.