In 1927 he was appointed Deputy Attorney General of South West Africa. Afterwards he entered politics and was elected to Parliament in 1933. He joined D F Malan's cabinet as the Minister of Defence in 1948. He was widely considered to be incompetent and was very unpopular because of his broad changes to the military to remove what he called the "British Influence". This included the removal of items such as the Red Tabs (Rooi Luise) and the retrenchment of firing of numerous english speaking officers and the appointment of Afrikaner ones in their place.
After his term as Minister of Justice he was appointed Ambassador to Italy.
^ abcWarwick, Dr Rodney (5 December 2014). "Let's not forget SA's role in WW2". politicsweb.co.za. Retrieved 13 December 2014. The NP government from 1948 cautiously distanced itself from the OB, however its main concern with the UDF was to Afrikanerize it as thoroughly and quickly as practical. This task was taken on by the unpopular and incompetent defence minister Frans Erasmus; supported by lackeys like the war "refusenik" Afrikaner nationalist Rudolf Hiemstra, who ultimately rose to the SADF Commandant-General position during 1965-73.