The Isle of Man Act 1958 provided for a major devolution of legislative power to Tynwald. However it did not meet the aspirations of the House of Keys for more democratic and responsible government. The period between 1958 and 1981 was marked by a lengthy but ultimately successful constitutional campaign by MHKs for a transfer of power within the Island, from the Lieutenant-Governor to Tynwald and within Tynwald to the elected chamber. Simultaneously, the Island was able to safeguard its newly won constitutional status in the face of threats posed by UK policies on devolution and Europe.

Political leadership was provided by Lieutenant-Governors and the most influential figures in the Legislative Council and the House of Keys, major changes in the balance of power between the Lieutenant-Governor and the branches of Tynwald helping to shape their respective roles. Four Lieutenant-Governors presided over Manx politics during this period, coming to the Island following a successful career in the colonial or armed services. Sir Ronald Garvey (1959–66) was born in 1903. Immediately prior to retirement from the colonial service, between 1952 and 1958, he was Governor of Fiji. His successor, Sir Peter Stallard (1966–73), was born in 1915. His appointment followed a five-year stint as Governor of British Honduras. The third appointee was Sir John Paul (1974–80). Born in 1916, he arrived in the Island in 1974 after presiding over the independence of the Bahamas. Sir Nigel Cecil (1980–85), who was born in 1925, succeeded Paul in 1980 after a distinguished career in the Royal Navy. In 1975 he was promoted to the rank of Rear Admiral and served as the last Commander of the British Forces in Malta from 1975 until his retirement in 1979. This quartet did not preside over the independence of the Isle of Man, but it was during their administrations that the office of Lieutenant-Governor was shorn of most of its political power and executive authority placed firmly in the hands of politicians responsible to Tynwald.

Those politicians were recruited from both the Legislative Council and the House of Keys. While this period saw the end of equal bicameralism in the Manx legislature, there was no immediate or willing acceptance by MLCs of political inferiority and members continued to play an important role in the legislative process, the Executive Council and boards of Tynwald.