Born in Holzendorf, Köppen joined military service in 1936 and initially served with a bomber before he was trained as a fighter pilot.

Köppen claimed his first aerial victories on 24 June 1941 during Operation Barbarossa, the German invasion of the Soviet Union.

Köppen was born on 17 May 1918, in Holzendorf, present-day part of Kuhlen-Wendorf, at the time in the Grand Duchy of Mecklenburg-Schwerin within the German Empire.

His initial posting was with Kampfgeschwader 1 "Hindenburg" (KG 1–1st Bomber Wing) before he was selected for fighter pilot conversion training in 1939.

Staffel was commanded by Oberleutnant Günther Rall and the Gruppe was headed by Major Gotthard Handrick.

On 21 June 1941, the Gruppe was ordered to Mizil in preparation of Operation Barbarossa, the German invasion of the Soviet Union.

The next day, the Gruppe moved to Mamaia, the northern district of Constanța on the Black Sea coast.

Gruppe with respect to number of aerial victories claimed, one behind his Staffelkapitän (squadron leader) Oberleutnant Günther Rall.

Gruppe had reached an airfield named Stschastliwaja located approximately 20 kilometers (12 miles) east-southeast of Oleksandriia.

Köppen's total number of aerial victories stood at 31 on 23 October, making him the leading fighter pilot of III.

[2] By the end of 1941, his total number of aerial victories had increased to 62, making him the most successful fighter pilot of III.

Gruppe had relocated to Zürichtal, a small village at the Inhul in the former German settlement west of Feodosia in the Crimea during the Crimean campaign.

[28] Following combat with a Petlyakov Pe-2 on 5 May, Köppen was posted as missing in action flying Messerschmitt Bf 109 F-4 "white 4" (Werknummer 7303—factory number) 10 km (6.2 mi) north of Ak-Monai (present-day Kam'yans'ke) near the Arabat Fortress.

His brother, Eckhardt Köppen, was killed in action on 15 January 1945; he was posthumously awarded the Knight's Cross on 15 March 1945.

[31] Spick lists Köppen with 85 aerial victories claimed in an unknown number of combat missions.