A Brexit deal that ensures no hard border on the island of Ireland has been hailed as a major victory for the country.
While Taoiseach Leo Varadkar said Brexit is "something we regret", he insisted the best possible withdrawal agreement has been negotiated.
He said other EU members had taken on Irish concerns and helped protect the peace process, the Common Travel Area and our economy.
"This is one of the better days in politics," he said.
Mr Varadkar praised British Prime Minister Theresa May for being "true to her word" by ensuring there will be no hard border.
However, Mrs May is still facing a massive battle to get the deal through UK Parliament in the coming weeks.
She used a tense five-hour meeting in London yesterday to convince her ministers that it is the only reasonable way forward. She said it was the only way to avoid a disorderly exit from the EU or "no Brexit at all".
The deal includes an Irish protocol, which ties Northern Ireland to the EU's customs union indefinitely.
It commits the UK to protecting "North-South cooperation and its guarantee of avoiding a hard border, including any physical infrastructure or related checks and controls, and bearing in mind that any future arrangements must be compatible with these overarching requirements".
The UK and EU have agreed to a 'backstop' whereby Northern Ireland will maintain "full alignment" with the rules of EU's internal market and the customs union "unless and until an alternative arrangement implementing another scenario is agreed".
Asked whether the guarantee of a soft border was 'cast iron', as claimed last December, Mr Varadkar said: "This is even stronger than what we had back in December."
He described the talks as "a difficult experience for everyone" but praised Mrs May's integrity.
Mrs May will deny that the deal amounts to the potential creation of a border down the Irish Sea.
The Common Travel Area, which allows Irish people travel freely back and forth to the UK, has also been preserved.
Although not legally necessary, the Cabinet has decided to have a vote on the deal in the Dail - but it is the vote in Westminster that will determine whether Mrs May's negotiating tactics have worked.
She told her Cabinet that the 585-page document makes it clear that the integrity of the UK is maintained. Her ministers rowed in behind the draft divorce package after a "long, detailed and impassioned" meeting.
Mrs May referred to the support from her Cabinet as a "collective agreement," but didn't say whether backing was unanimous.
She claimed the deal was "the best that could be negotiated", and "a decisive step which allows us to move on and finalize the deal in the days ahead."
"I firmly believe, with my head and my heart, that this is a decision which is in the best interests of the United Kingdom," she said.
Earlier, Mrs May told the House of Commons that the draft deal "takes us significantly closer to delivering what the British people voted for in the referendum" of 2016 that opted to leave the EU.
But the DUP, who prop up her minority government, last night looked set to abandon Mrs May.
"She has said that she will not break up the United Kingdom, there will be no difference between Northern Ireland and the rest of the United Kingdom," DUP leader Arlene Foster said of the UK Prime Minister.
"If she decides to go against all of that, then there will be consequences."
In Brussels, the EU's negotiator Michel Barnier said a deal would prevent the return of any "hard border" in Ireland by allowing all of the UK to remain within a customs union.
"We have now found a solution, along with the UK, to avoid a hard border on the island of Ireland," he said.
He added that a special North "backstop" would only be used if the two sides fail to reach a broader agreed within a 21-month transition.
The deal, and its endorsement by the UK cabinet, comes after 19 months of intense talks between EU and UK officials, which were overshadowed by a series of bitter rows and high-profile resignations in London.