The appointment of the Sinn Fein vice-president is a pivotal moment for Irish nationalism as it ends the dominance of pro-British unionists as first ministers.
Taking up the post, she pledged to work with unionists to build a better future for Northern Ireland and work “tirelessly” to improve the country alongside DUP MLA Emma Little-Pengelly, who was nominated as deputy first minister.
Addressing the chamber after her appointment was confirmed and she affirmed the pledge of office, Ms O’Neill said the restoration of the institutions marked a “moment of equality and progress”.
“A new opportunity to work and grow together,” she said. “Confident that wherever we come from, whatever our aspirations, we can and must build our future together.”
The two top jobs in the ministerial executive wield equal power and responsibility but the elevation of a republican to the office of first minister, by virtue of Sinn Fein becoming the region’s largest political party in the 2022 assembly election, is undoubtedly a significant symbolic moment for Northern Ireland.
The devolved government reconvened after the DUP, the largest unionist party in the region, walked out in February 2022 in protest at the UK’s post-Brexit trade arrangements.
It agreed to stop its boycott after getting fresh concessions from party leader Sir Jeffrey Donaldson which he says has effectively removed the Irish Sea trading border on goods remaining within the UK.
The proceedings commenced with the process of nominating a speaker, with former DUP leader Edwin Poots elected to the role.
Ms O’Neill said the public was “relying on each of us to act in their best interests and to serve our whole community in good faith.
“We must make powersharing work because collectively, we are charged with leading and delivering for all our people, for every community,” she said.
“In common cause, we must make life better for workers, families, communities. To create hope and opportunity.”
Ms O’Neill urged all MLAs to be “respectful of each other”.
“The days of second-class citizenship are long gone,” she said. “Today confirms that they are never coming back.
“As an Irish republican, I pledge cooperation and genuine honest effort with those colleagues who are British, of a unionist tradition and who cherish the union. This is an assembly for all – Catholic, Protestant and dissenter.
“Despite our different outlooks and views on the future constitutional position, the public rightly demands that we cooperate, deliver and work together.
“We must build trust and confidence in our ability to do that. That will require courage and ambition not just from us who are elected but from the public.
“We can all invest in this and the more of us that do the better the chance it has.”
The republican leader said those in the new ministerial executive “undoubtedly face great challenges” as she listed the issues besetting public services in the region.
She said ministers had to work together to challenge the UK government to provide more funding for Northern Ireland.
Northern Ireland secretary Chris Heaton-Harris hailed the restoration of powersharing while addressing media in the Great Hall in Stormont following the nomination of First Minister Michelle O’Neill, Deputy First Minister Emma Little-Pengelly and Speaker Edwin Poots.
“It’s a great day for Northern Ireland, it’s a great day for everyone here, a great day for businesses across this place and public services here,” he said.
And Irish minister for foreign affairs Micheal Martin hailed the “special day for the people of Northern Ireland”.
The tanaiste also congratulated Ms O’Neill and Ms Little-Pengelly on their appointments.
“I wish them both well in what will be very demanding roles. I look forward to working with them, and with their executive colleagues,” he said.
“I also want to congratulate Edwin Poots on his election as speaker of the assembly.”
Referring to the long path ahead, Mr Martin added: “While the last few weeks and months have focused on restoring the assembly and executive, the hard work now begins in earnest.
“Northern Ireland faces a number of real challenges. An executive working collectively – and prioritising real, everyday needs over questions of identity – can meet these challenges.
“The [Irish] government stands ready to support the work of the executive and to work in partnership with the British government in this.”