on 1 June 1942 With the outbreak of the
Second World War, the German Army High Command (the
OKH) assumed its wartime organisation. Heusinger accompanied the field staff and assisted in the planning of operations for the
invasions of Poland,
Denmark,
Norway, and
France and the Low Countries. He was promoted to colonel on 1 August 1940 and became chief of the
Operationsabteilung in October 1940, which made him number three in the army's planning hierarchy, after the Chief of the General Staff, General
Franz Halder, and the Deputy Chief of the General Staff/Chief Quartermaster, General
Friedrich Paulus. After the
invasion of the Soviet Union in June 1941, the OKH became responsible primarily for planning operations in that theatre, and the Armed Forces High Command (
Oberkommando der Wehrmacht, or OKW) was responsible for other theatres. Halder was replaced as Chief of the General Staff in September 1942 by General
Kurt Zeitzler. Heusinger remained chief of the
Operationsabteilung and was promoted to
Generalleutnant on 1 January 1943. In June 1944, Zeitzler suffered a nervous breakdown and abandoned his post, and on 10 June, Heusinger temporarily assumed his office as Chief of the General Staff of the Army. In this capacity, he attended the meeting at Hitler's
Wolf's Lair on 20 July 1944, and he was standing next to Hitler when the bomb exploded that had been planted by
Claus von Stauffenberg. Heusinger was hospitalised for his injuries in the explosion, but was later arrested and interrogated by the
Gestapo to determine his role, if any, in the
20 July plot. Although there was evidence that Heusinger had contacts with many of the conspirators, like all other high-ranking Wehrmacht military leaders, there was no evidence to connect him to the plot, and he was released in October 1944. According to Heusinger's own autobiography, he published an essay ("Denkschrift"), which Hitler received very positively. Heusinger made available all information that he had on the conspirators who had plotted against the Führer. He reaffirmed that he had not participated in the assassination plot since he still felt an obligation to fulfil his duty as a soldier of the German Reich, despite his personal view that the war had been lost. After his release, he was placed into the
Führerreserve, a reserve army of high-ranking German military leaders awaiting assignments, and was not assigned to another position until 25 March 1945, when he was made chief of armed forces mapping department (
Chef Wehrmacht-Kartenwesen). He was later taken prisoner by the Western Allies in May 1945. ==Postwar==