Leibbrandt was born to ethnic German parents in Hoffnungstal, near Odessa, in the Zebrikovo district of the Kherson Governorate of the Russian Empire. At an early age he emigrated to Germany for his studies. In 1918, Leibbrandt studied theology in Germany, also taking classes in philology and history. In 1927, he was awarded a Ph.D. He traveled extensively through the Soviet Union in 1926, 1928 and 1929. During his visits, he was variously represented as a doctor of philosophy, a post-graduate student, a professor of history from Leipzig University, and an employee of the Institute for the Study of Germans Abroad in Stuttgart. The official purposes of his visits were the study of the history of the development of German colonies in the Black Seacoastal region, and the gathering of historical information. As a result of his work, a book regarding emigrant movement of the Germans was published in Germany. Leibbrandt had a talent for languages, which, coupled with a Rockefellerscholarship, enabled him to resume his studies in Paris and the United States from 1931-33. While in the US he actively kept contact with Germans from Russia who had also immigrated to America.
Nazi Party
Leibbrandt accepted a request from Alfred Rosenberg in 1933 to return to Germany, and joined the Nazi Party that year. He was then named director of the Eastern Division of the Foreign Policy Office of the NSDAP. Leibbrandt was also placed in charge of anti-Soviet and anti-Communistpropaganda. When the Soviet Union was invaded in 1941, and the Ministry for the Eastern Occupied Territories was established, Rosenberg chose Leibbrandt to direct the Political Department. Thus, Leibbrandt became the liaison for the Ukrainian, Caucasian, Russian and other groups of emigres. Leibbrandt and Alfred Meyer attended the Wannsee Conference in 1942; both represented the Ostministerium. In the summer of 1943, for unknown reasons, he ceased his duties in the Ministry and joined the Kriegsmarine.
Later life
Leibbrandt was kept in Allied internment from 1945 to May 1949. In January 1950, he was formally charged with involvement in the destruction of Jews, by the Nuremberg Landgericht. The case against him was dismissed on 10 August 1950 and he was released from custody. He then returned to America and resumed his earlier studies on the subject of the Russian Germans, making expert contributions to the Association of Germans from Russia until his death in Bonn on 16 June 1982. Leibbrandt has a son of the same name, living in Berlin.