He was credited with 129 aerial victories claimed in 319 combat missions, all on the Eastern front of the Second World War.

[3] On 8 July 1943, Eisenach was wounded in his Focke-Wulf Fw 190 A-5 (Werknummer 1503—factory number) during combat with Douglas A-20 Havoc bombers northeast of Panino.

On this occurrence, his Fw 190 A-6 (Werknummer 530391) was shot down by anti-aircraft artillery 4 kilometres (2.5 miles) northwest of Gorodok, south of Nevel.

Staffel of JG 54, succeeding Hauptmann Herbert Aloé who had been killed in action on 21 June.

[8] On 8 August 1944, Eisennach was appointed Gruppenkommandeur (group commander) on I. Gruppe of JG 54.

Thad day, Eisenach claimed his 100th victory on 14 September 1944 by shooting down an IL-2 Sturmovik.

[12] That day, he became an "ace-in-a-day" claiming nine aerial victories, include five Ilyushin Il-2 ground attach aircraft and four Petlyakov Pe-2 twin-engined dive bombers.

[17] Spick also lists Eisenach with 129 aerial victories claimed in 319 combat missions, all of which on the Eastern Front.

[18] Mathews and Foreman, authors of Luftwaffe Aces — Biographies and Victory Claims, researched the German Federal Archives and also found confirmed records for 129 aerial victories for 154 claims filed.

The Luftwaffe grid map (Jägermeldenetz) covered all of Europe, western Russia and North Africa and was composed of rectangles measuring 15 minutes of latitude by 30 minutes of longitude, an area of about 360 square miles (930 km2).