A member of the
Nazi party from before 1933, Griebert worked as an advisor for the
Reich Chamber of Fine Arts in Berlin from 1934 to 1937. At the Reich Chamber of Fine Arts, his role was to ensure that art exhibitions respected
Nazi ideology. In 1938-1939 he advised the
Berlin National Gallery He also worked with the Nazi looting organisation known as the E.R.R.
(Einsatzstab Reichsleiter Rosenberg) and had ties to convicted Nazi art looter
Bruno Lohse who stayed with the Grieberts after Lohse's release from prison in 1950. Benno Griebert's son, Peter, became close to Lohse. When Nazi looted art was discovered in the vault of Lohse's Foundation Schonart, the only person authorized to access it was reportedly the younger Grieber. Benno Griebert was, along with
Fritz Nathan, a key dealer for the controversial art collector
Emil Bührle. == Postwar activities ==