The SDLP deputy leader Nichola Mallon has lost her seat in North Belfast to Alliance's Nuala McAllister.
It comes on the second day of counting in the Assembly election 2022 with Sinn Fein firmly on course to emerge as the largest Stormont party.
Ms Mallon has also been serving as Infrastructure Minister for the past two years.
Results in full: See every result in every constituency
She was first elected as a SDLP MLA for North Belfast in May 2016. Previously she represented the Oldpark DEA on Belfast City Council for six years and was the city's Lord Mayor in 2014.
In a statement posted alongside a photo of her three children, Ms Mallon said: "It has been a privilege to serve the people of North Belfast as a Councillor and then a MLA for the past 12 years. I want to thank every single person who came out to vote for me over that time. Time for a new chapter and lots and lots of time with these three."
Belfast North's count was the last to be completed at Belfast's TEC, with the five new MLAs taking to the stage at 6pm on Saturday.
Along with Nuala McAllister, Sinn Féin took two seats, with Gerry Kelly and Carál Ní Chuilín securing their MLA roles. The DUP's Phillip Brett and Brian Kingston stood together as their names were called out as newly elected representatives.
Under Stormont rules, if a sitting Executive Minister fails to get re-elected, the legislation is clearly defined.
The vacated seat returns to the political party which nominated the Minister and that party then has seven days to nominate a replacement.
The Northern Ireland Protocol has cast a long shadow over the election campaign following the resignation of First Minister Paul Givan in February in an effort to force the UK Government to act over the post-Brexit trading arrangements.
This action left the Executive unable to fully function.
While ministers like Ms Mallon remained in post, they were restricted in the actions they could take.
On Friday newly elected South Belfast MLA Matthew O'Toole described it was a difficult day for the SDLP.
Mr O'Toole was the final Assembly member to be elected at the Titanic Exhibition Centre late on Friday night.
He said while it felt good to be elected, it had been a tough day for his colleagues in the SDLP.
He said there had been a shift within nationalism towards Sinn Fein in response to a focus on the prospect of the party potentially topping the poll and being able to nominate a First Minister.
That would be the first nationalist or republican First Minister in the history of the Northern Ireland Assembly.
SDLP veteran Dolores Kelly lost her seat in Upper Bann, and there were fears over the fate of some others as the counting goes on in the Stormont election.
Daniel McCrossan, who was elected for the party in West Tyrone on Saturday, admitted it had been a tough election for the nationalist party.
He offered his full support to party leader Colum Eastwood and defended how the SDLP ran its campaign.
"I think Colum Eastwood has led this election very, very strongly. I think the campaign has been energetic, we have had fantastic candidates. I'm talking about politics here in the north of Ireland.
"At this election, everyone on the doors told me they wanted change, the reality is the exact same mandate, only in slightly greater numbers, has been given to the DUP and Sinn Fein. Is that an election for change?"
Read more: South Belfast NI election results: Two for Alliance as Green Party's Clare Bailey loses seat
Read more: NI Election 2022 analysis: Politics in Northern Ireland now has not two, but three tribes
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