The Nazi Party promised that there would be more jobs after the seizure of power, a reason which motivated Frenzel when he joined both the party and the Sturmabteilung (SA) in August 1930. His brother, a theology student, had joined the Nazi Party the previous year. His father joined the party in 1934. Frenzel claimed that antisemitism was an aspect of the politics to which they were indifferent. He later claimed that he was appalled by the early persecution of Jews in Germany.