The son of a lawyer, he studied economics, journalism, and law in Munich, Berlin, and Erlangen and was awarded his doctorate in law in 1933. Frauendorfer had already joined the Nazi Party and the SS in 1928, straight after graduating from the humanistic Ludwigsgymnasium in Munich, and was actively involved in the Nazi movement. The young attorney, holder of the Golden Party Badge, had swiftly risen through the ranks of the Nazi Party's Reich administration by the mid-1930s.
In 1934, he was appointed as the Nazi Party's Reich Head of Training as well as Head of Training of the German Labor Front (DAF), being subsequently promoted to SS Senior Assault Unit Leader (Obersturmbannführer) in 1935. In 1936, Frauendorfer moved to the Nazi Party's Reich Legal Office under Hans Frank. After the outbreak of the war, he followed Frank to the newly established general government for the occupied Polish territories, where he was in charge of the compulsory recruitment of Polish and Jewish labor as head of the labor administration. In this position, he found himself increasingly coming into conflict with the SS and police officers, as the extermination policy that they were pursuing hampered consistent use of the people for forced labor. At the end of 1942, he was granted leave and enlisted in the Wehrmacht.
When the war ended, Frauendorfer went into hiding to avoid having to surrender to the Polish. He lived under an assumed name in the Allgovia region and in Munich. He came out of hiding and submitted himself to denazification proceedings in 1950. Frauendorfer appealed against his classification as an 'Offender.' Thanks to some high-profile supporters and his characterization of himself as a resistance activist, the proceedings were dropped in 1951. He embarked on a new career in the private sector, quickly rising to executive level at Allianz Insurance in Munich.
He joined the Christian Social Union (CSU) in 1956. In 1958, he ran for the Bavarian Parliament, but had to withdraw his candidacy after his Nazi past came to light. In 1961, Frauendorfer was elected deputy state treasurer of the CSU due to his solid connections within the private sector and was nominated again to run for a seat, this time in the Bundestag (German Federal Parliament). Nonetheless, when he attempted to assume his mandate as a successor in 1963, he was once again thwarted by ongoing protests from a critical public. As a result, Frauendorfer lost his executive position at Allianz as well as his party office. A 1963 investigation into alleged Nazi atrocities was dropped without indictment, however. Frauendorfer lived in seclusion on Lake Starnberg until his death.
