After Heinz Knocke attended Jagdfliegerschule 1 in August 1940 he received his first combat posting, joining II./JG 52 In early 1941. The Gruppe was commanded by Hptm Erich Woitke and his new comrades included the future aces such as Gerhard Barkhorn, Günther Rall and Walther Krupinski.

Knocke first saw combat during the invasion of Soviet Union in June 1941, mostly conducting ground attack missions. However soon to be transferred to 2./JG 1 in July 1941 and the base Jever at the German North Sea coast. Here the pilots in the Gruppe flying in the home defense mostly trying to intercept Bittish reconnaissance flights.

In February 1942, Lt. Knoke participated with 3./JG 1 in Operation Donnerkeil, the Chanell Dash of the German battleships Scharnhorst and Gneisenau and heavy cruiser Prinz Eugen. However on 14 February 1942 Knoke was detached to Jagdgruppe Losigkeit, where he was charged with the air protection of these ships over the Norway coast.

He would score his first abschuss on 5 March when sharing a RAF Spitfire from No. 1 Photo Reconnaissance Unit. The next day, on a transfer flight led by Hptm. Werner Dolenga he was one of three pilot that was forced to belly land their Bf 109 Emils due to running out a gas. Heinz Knocke put down his "Black 3" at the ice close to Alvdal south of Röros in Norway and was picked up a day later. In October 1942 Knoke became the Staffelkapitän of 2./JG 1 and on 31 October he claimed his second victory, a RAF Blenheim.

Later a Knight's Cross recipients Heinz Knocke logged over two thousand flights, four hundred combat missions and was officially credited with a total of thirty-three abschüsse, although in his well known Memoires "I Flew for the Führer" his tally is by himself quoted as 52 victories.