Created under the terms of the 1998 Good Friday Agreement, both were initially nominated and appointed by members of the Northern Ireland Assembly on a joint ticket by a cross-community vote, under consociational principles.

The First Minister is, though, the first to greet official visitors to Northern Ireland and shares the same title as their counterparts in Scotland and Wales.

The incumbent junior ministers are Aisling Reilly (Sinn Féin) and Pam Cameron (Democratic Unionist Party).

Following several suspensions of the Northern Ireland Executive, Trimble was not re-elected on 2 November 2001 due to opposition from other unionist parties.

He was subsequently re-elected alongside Mark Durkan (SDLP) on 6 November 2001; on that occasion, three Alliance Party of Northern Ireland MLAs redesignated from 'other' to 'unionist' to support Trimble's nomination.

[14] Following the St Andrews Agreement in October 2006, the appointment procedure was changed to allow for: This procedure, which removed the need for a joint ticket between the unionist Democratic Unionist Party and the nationalist Sinn Féin party, was used to appoint Ian Paisley and Martin McGuinness on 8 May 2007.

[13][15] Vacancies have occurred on four occasions to date: In the Irish language, the literal translation of these positions is "Céad-Aire agus an leas Chéad-Aire".

The titles appear in both English and Irish in published literature by the North-South Ministerial Council, one of the "mutually inter-dependent" institutions laid out in the Good Friday Agreement, along with the Northern Ireland Assembly.

Several weeks after Martin McGuinness took up office as Deputy First Minister in 2007, civil servants in his department began asking the Assembly's Hansard team to replace the capital 'D' with a lower-case 'd', pointing out that the title was rendered that way in the Northern Ireland Act 1998, the legislation which established the office.

[26] With the restoration of power-sharing in 2020, Sinn Féin started describing the position as "joint head of government".

Eventually, on 2 December 1999, power was devolved and Trimble and Mallon formally took office as joint heads of the Northern Ireland Executive.

Arlene Foster succeeded Peter Robinson as DUP leader on 18 December 2015, and as First Minister on 11 January 2016.

[34] Despite concerns by Sinn Féin that an Irish Language Act would not pass, following talks with the British government they agreed to renominate Michelle O'Neill for deputy First Minister.