She served as a Member of Parliament from 1973 to 1989, representing the county of Nordland, as the first parliamentary leader of the Socialist Left Party from 1977 to 1989.
She worked for the thoroughly nazified German Red Cross in the ending years of the Second World War, and she was convicted for treason following her repatriation to Norway in 1947.
After the German defeat, she was interned in the British sector of Germany; she was returned to Norway in late 1947 where she was tried and convicted for treason.
Kvanmo joined local politics in Rana, and in 1973 she was elected to the Storting, representing the Socialist Left Party (SV).
She was highly critical of Egyptian President Anwar Sadat and Israeli Prime Minister Menachem Begin for their efforts of negotiating Israeli–Egyptian peace in the late 1970s.