During World War II, he was General Commissioner of Generalbezirk Litauen and was involved in perpetrating the Holocaust in Lithuania.
Of Baltic German origin, von Renteln studied law and economics in Berlin and Rostock, but became a journalist.
In June 1933, he was appointed President of the National Socialist Council of Industry and Trade (Nationalsozialistische Handwerks-, Handels-, und Gewerbeorganisation or NS-HAGO), holding this position until 1935, when this organisation was merged with the German Labor Front (DAF).
In July 1941, he was appointed the Generalkommissar of Generalbezirk Litauen (roughly modern Lithuania), where he took harsh measures against the Jewish population.
On 26 August 1941 he ordered that all telephones and lines were to be stripped, postal service be cut off, and bridges to the Kaunas (Kovno) Ghetto be surrounded with barbed wire fences to prevent people from jumping off.