In summer 1939, Wolff began working at Adolf Hitler's headquarters as Himmler's representative. He served as an intermediary between the SS and the state administration. Easing administrative friction caused by the "final solution" (the Holocaust) was one of his primary tasks. Wolff secured transport to carry out the deportations of Jews to the death camps.
On 30 January 1942, Wolff was promoted to SS-Obergruppenführer and general of the Waffen-SS, but, isolated in Hitler's headquarters, he lost control of Himmler's entourage. In September 1943, he became the highest SS and police official in Italy. In charge of fighting the Italian Resistance, he was therefore responsible for the massacres of civilians.
By early 1945, Wolff became convinced that Germany would lose the war, and he made contact with the Allies. He signed a treaty of unconditional surrender at the Italian front on 2 May 1945, one week before the general capitulation. Arrested after the war and charged with minor crimes, he was sentenced to four years but spent only a week in prison.
Wolff was working as a businessman in Köln (Cologne) when new evidence against him emerged. In 1962, he was arrested and charged with committing genocide. Found guilty in 1964, he was sentenced to 15 years in prison but was released in 1971. Wolff died in Rosenheim, Bavaria, Germany, on 15 July 1984.
Koehl, Robert Lewis. The Black Corps: The Structure and Power Struggles of the Nazi SS. Madison: University of Wisconsin Press, 1983.; Lang, Jochen von. Der Adjutant: Karl Wolf—Der Mann zwischen Hitler und Himmler. Frankfurt, Germany: Ullstein, 1985.