Marseille joined the Luftwaffe, the air force of Nazi Germany, in 1938. At the age of 20 he participated in the Battle of Britain, without notable success. As a result of poor discipline, he was transferred to another unit (JG 27), which relocated to North Africa in April 1941.
Under the guidance of his new commander, Marseille quickly developed his abilities as a fighter pilot. He reached the zenith of his career on 1 September 1942, when during the course of three combat sorties he claimed 17 fighters shot down, for which he received the Knight's Cross of the Iron Cross with Oak Leaves, Swords and Diamonds. A month later, Marseille was killed in a flying accident after his aircraft suffered engine failure. Forced to abandon his fighter, Marseille struck its vertical stabiliser and was either killed instantly or incapacitated and unable to open his parachute.