Friedrich W. Rainer (28 July 1903 – 19 July 1947) was an Austrian Nazi politician, Gauleiter as well as a State governor of Salzburg and Carinthia.
He is the only Austrian governor who has ever held the same office in two separate states. Rainer was a native of Sankt Veit an der Glan in Carinthia, the son of a vocational teacher at a municipal Bürgerschule (secondary school). Following his general education, Rainer studied law at the University of Graz and earned his living by working in a local banking institution or in general labor. After successfully completing his law examination, Rainer began working in a notary's office. Prior to his graduation from law school in 1926, he joined the Austrian SA, and served as a member of organizations based in St. Veit that were propagating the political rhetoric of Nazism.
In October 1930, Rainer joined the Nazi Party establishing the local branch in Sankt Veit. Four years later, he joined the SS and took up a post at the office of Nazi Gauleiter Hubert Klausner in Klagenfurt. As the Nazi Party had been banned by the Austrian government under Engelbert Dollfuß in 1933, Rainer in August 1935 was sentenced to one year in police custody, presumably for high treason. He was released early for good behaviour the following March, nevertheless like Klausner and his deputy Odilo Globocnik he had to step down from his administrative role in the party, transferring sole leadership to the rivalling Austrian Nazi leader Josef Leopold. As Leopold soon fell out of favour with Adolf Hitler, Friedrich in May 1936 was again assigned to the Nazi Party's provincial body in Carinthia.
In the course of the Austrian Anschluss to Nazi Germany on 13 March 1938, Rainer was recruited to serve as the organizational staff leader by Reichskommissar Josef Bürckel. On 22 May 1938, Rainer was personally appointed by Hitler to oversee the Nazi Party in the Reichsgau of Salzburg. That same year, he became a member of the Reichstag parliament in Berlin. He remained in his Gauleiter role at Salzburg, until 18 November 1941, when he was succeeded by Gustav Adolf Scheel.
When the Second World War broke out, Rainer was appointed as Reich Defence Commissar of the military district XVIII. On 15 March 1940, he was additionally appointed as the Reichsstatthalter (Reich Governor) of Salzburg. On 18 November 1941, Rainer was appointed as the Party's Gauleiter of Carinthia, while simultaneously functioning in the role of a governor, thereby also ruling over the adjacent occupied Yugoslavian territories in Upper Carniola. On 11 December 1942, Rainer was made Reich Defence Commissar of Carinthia, much like his role in Salzburg. After Italy abandoned its German ally on 10 September 1943, Rainer took over the Operational Zone of the Adriatic Littoral as High Commissioner in the rank of a SS–Obergruppenführer. This act established him as the chief of the civil administration in the Italian region of Friuli, as well as in Yugoslavian Istria and Inner Carniola.
On 7 May 1945, eight days after Hitler's death, Rainer transferred his official functions to an executive board and fled to the mountainous area around the Weißensee lake in Carinthia. After being given leads by the local population, British occupation troops arrested Rainer and transferred him to Nuremberg, where he was compelled to testify in the Nuremberg Trials against the 24 main defendants, specifically in the case against the former Austrian chancellor Arthur Seyss-Inquart.
On 13 March 1947, Friedrich was extradited to Yugoslavia. On 10 July 1947, he was brought before a military court of the Yugoslav 4th Army at Ljubljana. He was found guilty of crimes against the people and sentenced to death on 19 July 1947. His widow received a death certificate from Yugoslavia after the war, which showed that same date. Nevertheless, as in similar cases, rumours lingered on into the 1950s that Rainer was still alive, working for the Yugoslav Department of State Security.