ST. IVES, England — President Biden and British Prime Minister Boris Johnson met for the first time Thursday and underscored the history and durability of transatlantic ties as they focused on common goals such as ending the coronavirus pandemic and combating climate change.

“We affirmed the special relationship — it’s not said lightly — the special relationship between our people,” Mr. Biden said after the meeting. “We renewed our pledge to defend the enduring democratic values that both of our nations share that are the strong foundation of our partnership.”

Though thorny issues like Britain’s exit from the European Union and the future of Northern Ireland shadowed the meeting, Mr. Biden and Mr. Johnson began their sit-down by immediately striking a tone of conviviality.

“I told the prime minister we have something in common. We both married way above our station,” Mr. Biden joked after a walk with their spouses.

“I’m not going to disagree with you on that,” Mr. Johnson laughed, “or indeed on anything else.”

The two leaders agreed to an updated version of the Atlantic Charter, an 80-year-old statement of solidarity between Washington and London that was originally signed by President Franklin D. Roosevelt and Prime Minister Winston Churchill in 1941 governing technology, travel, and trade ties between the two nations.

The new document details eight areas of agreement, expressed mostly in broad strokes with few specifics, starting with a “resolve to defend the principles, values, and institutions of democracy and open societies, which drive our own national strength and our alliances.”

The two leaders pledged to “strengthen the institutions, laws and norms that sustain international cooperation to adapt them to meet the new challenges of the 21st century.”

One senior administration official described the document as “a profound statement of purpose of democracy,” coming at a time when Mr. Biden has repeatedly outlined an existential struggle for the future of the globe between democracy and autocracy.

The agreement falls short of the independent U.S.-U.K. trade deal that Mr. Johnson wants now that Britain’s exit from the European Union is complete.

Mr. Biden has indicated that he could withhold such a deal over concerns that Mr. Johnson’s government is undermining the 1998 Northern Ireland peace agreement that ended three decades of sectarian conflict.

“Any steps that imperil or undermine it will not be welcomed by the United States,” national security adviser Jake Sullivan said.

Mr. Johnson announced that the Group of Seven nations are prepared to commit to sharing at least 1 billion coronavirus shots with the world, with half coming from the United States and 100 million from the United Kingdom.

Mr. Biden urged allies to join in speeding the pandemic’s end and bolstering the strategic position of the world’s wealthiest democracies.

“We’re going to help lead the world out of this pandemic working alongside our global partners,” Mr. Biden said, noting that on Friday the G7 nations will join the United States in outlining their vaccine donation commitments.

The G7 also includes Canada, France, Germany, Italy, and Japan.

The prime minister’s office said the first 5 million U.K. doses would be shared in the coming weeks, with the remainder coming over the next year.

Mr. Biden’s commitment was on top of the 80 million doses he has already pledged to donate by the end of June.

“At the G7 Summit I hope my fellow leaders will make similar pledges so that, together, we can vaccinate the world by the end of next year and build back better from coronavirus,” Mr. Johnson said in referencing Mr. Biden’s campaign slogan.

Earlier Thursday, French President Emmanuel Macron welcomed the U.S. commitment and said Europe should do the same.

He said France would share at least 30 million doses globally by year’s end.

The G7 leaders have faced pressure to outline their global vaccine sharing plans, especially as inequities in supply around the world have become more pronounced.

In the United States, there is a large vaccine stockpile and the demand for shots has dropped precipitously in recent weeks.

Mr. Biden predicted the U.S. doses and the overall G7 commitment would “supercharge” the global vaccination campaign, adding that the U.S. doses come with no strings attached.

He said the 500 million U.S.-manufactured vaccines will be shipped starting in August, with the goal of distributing 200 million by the end of the year.

The remaining 300 million doses would be shipped in the first half of 2022.

A price tag for the doses was not released, but the United States will become COVAX’s largest vaccine donor in addition to its single largest funder with a $4 billion commitment.

Mr. Biden, in his remarks, harked back to the Detroit-area workers who 80 years ago built tanks and planes “that helped defeat the threat of global fascism in World War II.”

“They built what became known as the arsenal of democracy,” Mr. Biden said. “Now a new generation of American men and women, working with today’s latest technology, is going to build a new arsenal to defeat the current enemy of world peace, health, and stability: COVID-19.”

He noted that Pfizer’s main vaccine plant in Kalamazoo, Mich., is not far from Detroit.

After the two leaders met, Mr. Johnson told British broadcasters that his U.S. counterpart’s approach is a “breath of fresh air” and that their talks had gone well.

The Biden Administration has tried to play down Mr. Biden’s concerns that Mr. Johnson’s government may undermine the historic Good Friday peace agreement with Northern Island.

Biden aides point instead to the long list of shared priorities and joint endeavors, including nearly 20 years fighting together in Afghanistan.

“The U.K. was with us from the start — they always are — equally committed to rooting out that terrorist threat,” Mr. Biden said after the two leaders met.

He did not lavish his host with praise and he did not hold a news conference alongside Mr. Johnson, previously a standard feature of visits by leaders of either nation to the other.

Mr. Biden did not mention the Northern Ireland issue publicly, but officials of both governments said it was discussed.

Mr. Johnson said the President did not push him on the issue Thursday, but said that maintaining peace in Northern Ireland and supporting the Good Friday Agreement was “absolutely common ground” between Washington and London.

A joint statement issued after the meeting said both nations would “reaffirm their commitment to working closely with all parties to the agreement to protect its delicate balance and realize its vision for reconciliation, consent, equality, respect for rights, and parity of esteem.”

Mr. Biden’s Irish Catholic heritage is a central feature of his long political career. He opposed Britain’s E.U. exit in part on principle because it cleaved a major economy and U.S. ally from the European Union, and partly out of concern that it would reopen wounds with Ireland, which remains part of the European Union.

Irish officials have said they welcomed the Biden Administration’s focus on the dispute over the border with Northern Ireland, with Prime Minister Micheal Martin calling Mr. Biden’s interest in the issue a significant development.

First Published June 11, 2021, 2:03 a.m.