Historically, the principal ministers for Irish (and subsequently Northern Ireland) affairs in the UK Government and its predecessors were: In August 1969, for example, Home Secretary James Callaghan approved the sending of British Army soldiers to Northern Ireland.

[8] The secretary of state filled three roles which existed under the previous Stormont regime:[9] Direct rule was seen as a temporary measure, with a power-sharing devolution preferred as the solution, and was annually renewed by a vote in Parliament.

The Sunningdale Agreement in 1973 resulted in the brief existence of a power-sharing Northern Ireland Executive from 1 January 1974, which was ended by the loyalist Ulster Workers' Council strike on 28 May 1974.

The secretary of state is now generally limited to representing Northern Ireland in the UK cabinet, overseeing the operation of the devolved administration and a number of reserved and excepted matters which remain the sole competence of the UK Government e.g. security, human rights, certain public inquiries and the administration of elections.

The secretary of state exercises their duties through, and is administratively supported by, the Northern Ireland Office (NIO).

The devolved administration was suspended several times (especially between 15 October 2002 and 8 May 2007) because the Ulster Unionist Party and Democratic Unionist Party were uncomfortable being in government with Sinn Féin when the Provisional Irish Republican Army had failed to decommission its arms fully and continued its criminal activities.

During these periods, in addition to administration of the region, the secretary of state was also heavily involved in the negotiations with all parties to restore devolved government.