Max-Hellmuth Ostermann was born on 11 December 1917 in Hamburg. His father was a civil servant in the justice department. Ostermann joined the Luftwaffe as a "Fahnenjunker" (Officer Cadet) in March 1937 after he had received his "Abitur" (diploma)—the final exams that pupils take at the end of their secondary education. His first assignment was with I. "Gruppe" (1st group) "Zerstörergeschwader" 1 (ZG 1) flying the Messerschmitt Bf 110 and participated in the Invasion of Poland in 1939. In January 1940 "Hauptmann" (Captain) Wolfgang Falck took command of I./ZG 1. Falck came to the opinion that the Bf 110 was just a little too big for Ostermann and had him transferred to the Messerschmitt Bf 109 equipped I./"Jagdgeschwader" 21 (JG 21) on 7 April 1940. JG 21 at the time was based at Mönchengladbach and was subordinated to "Oberstleutnant" (Lieutenant Colonel) Max Ibel, the "Geschwaderkommodore" (Wing Commander) of "Jagdgeschwader" 27.