He was a member of the National (Country) Party and succeeded his father Sir Charles Adermann in federal parliament.

[4] He was appointed Minister for the Northern Territory following the Fraser government's win at the 1975 election and held it until its abolition in September 1978.

He put in place the arrangements for Northern Territory self-government and was responsible for the establishment of Uluru National Park and continuing the reconstruction of Darwin after Cyclone Tracy.

He was responsible for establishing an inquiry into the effects of Agent Orange on Australian servicemen who had fought in the Malayan Emergency and the Vietnam War.

Following a redistribution which transferred his home to the new Division of Fairfax, Adermann ran for this seat and won it at the 1984 election.