Mark Rutte, the long-serving Dutch prime minister, was formally named the new secretary general of NATO on Wednesday, putting an experienced, strongly pro-Ukraine leader with a reputation for conciliation at the head of the alliance.
Mr. Rutte, 57, will take over from Jens Stoltenberg on Oct. 1, at a difficult time for NATO in the face of Russia’s war against Ukraine and in the midst of a tight race for the American presidency that could bring Donald J. Trump, who disparages the alliance, back into power.
The decision, sealed by NATO ambassadors during a meeting at the 32-nation alliance’s headquarters in Brussels, removes a potentially contentious issue from the alliance’s 75th anniversary summit meeting next month in Washington.
President Biden and his NATO counterparts will formally welcome Mr. Rutte to their table at a summit, which begins on July 9.
Long a favorite of Mr. Biden for the post, Mr. Rutte served as the Dutch prime minister four times, for nearly 14 years, building complicated coalitions through debate and compromise. Those skills should serve him well in an alliance that works by consensus, where one country can block the intentions of the rest.
Mr. Rutte turned down Mr. Biden’s request that he seek the NATO job at least once before, forcing the alliance to extend Mr. Stoltenberg’s term for an extra year.
Now serving as a caretaker prime minister before a new Dutch government is sworn in, Mr. Rutte is known as a hard worker but an affable boss. A man of habit, the son of a car dealer, he has lived in the same modest house, with the same furniture, for the past 30 years.
Every summer, he rents the same house with family members and spends a few days each year in New York with the same friend, staying in the same modest hotel in Chinatown, wrote Caroline de Gruyter, Europe correspondent for the Dutch newspaper NRC Handelsblad, in Foreign Policy.
He is also known for riding his bicycle to work, a habit that will have to change because his new job will require him to endure significantly enhanced security wherever he goes. He will also have to drop the weekly social studies class he has taught for years at a high school in The Hague.
Mr. Rutte will take over with NATO struggling to find a way to reassure Ukraine of its long-term commitment to its security at a time when the country is facing increased Russian pressure after more than two years of war.
Allies are also concerned that Mr. Trump, who has been openly hostile to NATO and some of its leaders, could win back the presidency, although Mr. Rutte got along well with Mr. Trump when he was in office.
In February, speaking at the Munich Security Conference, Mr. Rutte told Europeans to “stop moaning and whining and nagging about Trump,” and instead act in their own interests by beefing up their militaries and producing more ammunition for Ukraine.
Americans will decide the next president, he said, adding: “I’m not an American, I cannot vote in the U.S. We have to work with whoever is on the dance floor.”
Mr. Rutte was the favorite of NATO’s largest countries, but he needed unanimity. He essentially clinched the job as secretary general last week when he agreed to abide by a compromise worked out between Mr. Stoltenberg and Prime Minister Viktor Orban of Hungary.
The illiberal democracy in Hungary espoused by Mr. Orban has been the source of tension for years with the European Union’s longest-serving leaders, including Mr. Rutte.
Mr. Rutte assured Mr. Orban, who is close to President Vladimir V. Putin of Russia and believes that Ukraine should negotiate a settlement with Moscow, that no Hungarian personnel would take part in NATO missions to support Ukraine, and no Hungarian funds would be used to support them
Slovakia, another skeptic, then agreed to back Mr. Rutte, and the final obstacle was cleared when the president of Romania abandoned his own bid to become the head of the alliance.
Mr. Rutte’s view of the Kremlin was deeply affected by the shooting down of Malaysia Airlines flight MH17 over Ukraine in 2014, with 196 Dutch people among the 298 people killed by a Russian antiaircraft missile that had been provided to separatist forces by the Russian military.
In September 2022, seven months after Russia’s invasion of Ukraine, Mr. Rutte told the United Nations of Mr. Putin: “He won’t stop at Ukraine if we don’t stop him now. This war is bigger than Ukraine itself. It’s about upholding the international rule of law.” He has described Mr. Putin as “coldhearted, brutal, merciless.”
Under Mr. Rutte, the Netherlands has increased military spending to more than the 2 percent of gross domestic product demanded of NATO members, and it has provided F-16 fighter jets, artillery, drones and ammunition to Kyiv while investing more in its own military.
Known in the Netherlands as “Teflon Mark” for his ability to create compromise and escape difficulties, he will find his skills tested in his new role, especially since the NATO secretary-general’s job is less to lead the large, diverse alliance than to keep it together.