Most cabinets in democratic systems form because the parties want to govern together. Northern Ireland's Executive forms because the parties have no legal choice. Ministerial portfolios are allocated by the D'Hondt method - a proportional formula that gives every party with significant Assembly seats at least one minister. The First Minister comes from the largest party in the largest community designation; the deputy First Minister from the largest party in the second-largest designation. The Minister of Justice requires cross-community support to be appointed. There is no opposition by default - every major party is entitled to ministers whether it wants them or not, though since 2016 parties can choose to decline and join an Official Opposition instead. The arrangement is called consociationalism by political scientists. It is designed to make exclusion impossible. The price is that any major party can collapse the system simply by withdrawing.

The Executive currently has nine departments, reduced from eleven in 2016. The Executive Office, run jointly by the First and deputy First Ministers, oversees cross-cutting issues and external relations. Then there are the line departments: Agriculture, Environment and Rural Affairs; Communities; Economy; Education; Finance; Health; Infrastructure; Justice. Health is consistently the largest, swallowing almost half of the £14 billion devolved budget. Education runs the controlled, maintained and integrated schools that divide most Northern Irish children along community lines. Infrastructure looks after roads, planning, water, and the lough crossings. Justice was the last department to be transferred from Westminster - it arrived only in April 2010 after years of negotiation, on condition that the Alliance Party hold it under a cross-community vote to depoliticise the role. Each department is headed by a minister who has full executive authority within their portfolio but limited authority to act unilaterally on cross-cutting issues.

There was an earlier attempt. The original Northern Ireland Executive formed on 1 January 1974 under the Sunningdale Agreement, a voluntary coalition of the Ulster Unionists, the SDLP, and Alliance, with UUP leader Brian Faulkner as Chief Executive. It included for the first time a Council of Ireland that gave the Republic a consultative role in Northern Irish affairs. Unionist opinion did not accept it. On 14 May 1974 the Ulster Workers' Council called a general strike that paralysed Northern Ireland - power stations stopped, milk deliveries failed, petrol stations closed - and after fourteen days of escalating chaos the Executive resigned on 28 May. Direct rule from Westminster resumed and lasted, with brief gaps, until 1999. The phrase 'Sunningdale for slow learners' was famously coined by SDLP politician Seamus Mallon to describe the 1998 Good Friday Agreement: the same architecture, the same parties roughly, twenty-four years later. The 1974 collapse was a cautionary tale that hung over every subsequent negotiation.

The current Executive has had to be reassembled repeatedly. From October 2002 to May 2007 it sat empty after a PSNI investigation - later called Stormontgate - alleged an IRA spy ring operating at Stormont; charges were eventually dropped but unionist trust did not return for nearly five years. From January 2017 to January 2020 it sat empty after Martin McGuinness resigned as deputy First Minister in protest over the Renewable Heat Incentive scandal, a green-energy subsidy that perversely paid claimants to burn wood pellets. Sinn Fein then refused to nominate his replacement until a deal on the Irish language and other matters was reached - the eventual 'New Decade, New Approach' agreement that restored devolution. From February 2022 to February 2024 it sat empty again after the DUP collapsed the institutions in protest at the Northern Ireland Protocol, the post-Brexit trading arrangement that put a regulatory border in the Irish Sea. Each time, the practical government of Northern Ireland fell to the civil service in a caretaker capacity, with no minister authorised to make significant new decisions.

Even during the long collapses, Northern Ireland continued to function - hospitals stayed open, roads were repaired, exams were sat, taxes were collected by HMRC. The civil service kept the lights on but could not introduce new policy or change spending priorities. Westminster passed budgets by Order in Council. Some decisions were quietly made by senior civil servants under emergency legislation. Westminster occasionally legislated directly on devolved matters: in 2019, during the 2017-2020 suspension, the UK Parliament legalised same-sex marriage in Northern Ireland and decriminalised abortion - both matters that Stormont, by then, had been unable to address for years. The Executive's existence is in this sense both indispensable and provisional. When it works, it makes decisions tailored to Northern Ireland by people elected by Northern Ireland. When it doesn't, the region's affairs are managed remotely, slowly, and without the political accountability that devolution was designed to provide. The current Executive has been functioning since February 2024. Whether that continues remains, as it has been since 1998, an open question.