Some European leaders jested they’d send Prime Minister Viktor Orban of Hungary their hotel bills for the extra nights they had to spend in Brussels to convince him to support funding for Ukraine.
Others, less jokingly, relayed to him he was facing the risk of a legal suspension from E.U. proceedings. And a few offered a friendly, sympathetic ear over late-night drinks as he complained about what he sees as a European bureaucracy stacked against him out of ideological animus.
By Thursday morning, just one hour into an emergency European Union summit meeting, this carefully coordinated, behind-the-scenes pressure had forced Mr. Orban to fold and agree to a landmark 50 billion euro ($54 billion) fund for Ukraine that will help the country stay afloat for the next four years, even as U.S. aid is stuck in Congress.
Playing different roles, these European leaders were central to the effort that finally got Mr. Orban on board — in a breakthrough not just for Ukraine but for E.U. unity as well.
European Council President Charles Michel was the bad cop. On Monday he called Mr. Orban to let him know there was no way he would be granted his demand for an annual veto right over the Ukraine fund. And he told Mr. Orban that some member states were considering launching a procedure that would strip him of his vote entirely — in what would be an unprecedented use of the E.U.’s rule book.
Then, on Wednesday evening, Mr. Orban met with Prime Minister Giorgia Meloni of Italy, his ideological friend from the hard right, in the executive suite of the stately Amigo hotel — a staple for visiting dignitaries, tucked away in the center of Brussels.
Sitting on green velvet armchairs against the leafy wallpaper, over a bottle of champagne, Ms. Meloni told him he had more to gain from the E.U. if he played along this time. She suggested that a review of the Ukraine fund in 2025 would go some way toward satisfying his need for close scrutiny of the spending.
Next up was Emmanuel Macron, the French president, who had hosted Mr. Orban for lunch in January in Paris. He met Mr. Orban at the Amigo later on Wednesday evening and suggested that E.U. leaders could include some language in their joint conclusions that would nod to Mr. Orban’s complaints about being treated unfairly by the E.U. executive branch.
All the while, Mr. Orban knew that a few miles up the street in the European quarter of Brussels, other leaders were meeting to talk about him — without him. A meeting between Mr. Michel, the Dutch prime minister, Mark Rutte, and the German chancellor, Olaf Scholz, confirmed that there was nothing to gain from holding out on the Ukraine fund.
That word was relayed back to Mr. Orban.
The efforts to get Mr. Orban to capitulate without budging were unusually complex, reflecting both his unique spoiler role and the importance of getting unanimous agreement on the Ukraine fund.
Small as his country is, Mr. Orban has made himself a big antagonist of E.U. rules and norms, drawing both rebukes and monetary punishments from his partners. He has also been an outsized obstacle to many of Europe’s ambitions, including some sanctions against Russia and even Sweden’s bid to join the NATO alliance.
Mr. Orban has repeatedly used the E.U. requirement for unanimity to push Brussels for concessions — including unfreezing money that has been withheld from Hungary to prod him to make democratic reforms.
Before Thursday’s meeting, Mr. Orban had been demanding an annual chance to veto the disbursement of money to Ukraine, but that was rejected. Instead, leaders agreed to a regular review of the spending to assuage concerns about diversion or corruption, E.U. officials said.
Under the agreement reached on Thursday, the European Commission, the E.U. executive arm, will draft an annual report on how the Ukraine fund is being used. European leaders will have a chance to debate its performance and raise any concerns about it.
The European Parliament needs to approve the fund by simple majority, a bar that should be easily cleared, and the vote could take place as early as this month.
“All 27 leaders agreed on an additional €50 billion support package for Ukraine within the EU budget,” Mr. Michel said on social media just an hour into Thursday’s meeting. “This locks in steadfast, long-term, predictable funding,” he added. “EU is taking leadership & responsibility in support for Ukraine; we know what is at stake.”
Talks had been gridlocked, and the mood toward Mr. Orban, the closest E.U. ally of the Russian president, Vladimir V. Putin, had been souring since he blocked the first Ukraine funding attempt in December.
Ukraine needs the money desperately to keep basic services running. The European aid, to be dispensed in the form of loans and grants over the next four years, would both cover immediate needs and allow Ukraine to plan its long-term budget.
Mr. Orban’s obstruction of the European Union’s support of Ukraine has been riling his European partners. He has held up or watered down support for Ukraine, including some sanctions against Russia, since the war began.
He has claimed that his resistance comes down to a fundamental disagreement with other European leaders: He does not believe Russia poses a security threat to Europe, nor does he think that the European Union should be throwing its weight behind Ukraine.
But Mr. Orban regularly uses his levers within the bloc — often his ability to veto decisions that require unanimity, such as the introduction of the Ukraine fund — to push for funding that he has lost access to in a longstanding dispute with the commission over his domestic policies.
The European Union and Hungary have long clashed over policies on the rule of law, corruption and minority rights.
The commission has taken Hungary to task over judicial appointments it says interfere with the independence of the courts; laws that discriminate against L.G.B.T.Q. people; and the defanging of anticorruption authorities. It blocked Hungary from gaining access to some €20 billion until it can demonstrate that it has altered those policies to bring them in line with E.U. rules and values.
If Mr. Orban’s demand for an annual veto for the Ukraine fund was a play to get access to more funding, it failed.
Officials on Thursday said that he had managed only to extract a reference in the summit conclusions urging the European Commission to be “proportionate” in the way it freezes funding for member states it punishes for violations, as is the case with Hungary.
The swift decision on Thursday was welcomed with relief by some E.U. leaders weary of the endless fights with Mr. Orban and eager to avoid another showdown that would harm the appearance of unity toward Ukraine.
Shortly after the agreement was announced, Prime Minister Mark Rutte of the Netherlands wrote on social media: “I’m delighted that we have reached agreement on support for Ukraine. This 50 billion euro package will help us achieve more structure, transparency and predictability in our financial aid to Ukraine.”
The message was clear, he added: “Ukraine can count on our support, both now and in the future.”
The news was also warmly welcomed in Ukraine.
“It is very important that the decision was made by all 27 leaders, which once again proves strong EU unity,” President Volodymyr Zelensky of Ukraine wrote on social media. “Continued EU financial support for Ukraine will strengthen long-term economic and financial stability, which is no less important than military assistance and sanctions pressure on Russia.”
Andrew Kramer contributed reporting from Kyiv, Ukraine.
