Among most messages was a palpable sense of relief, as the international community embraced Biden’s pledge to reenter a series of global pacts and organizations that President Donald Trump cut loose.
Here’s what leaders have said so far.
“Once again, after four long years, Europe has a friend in the White House,” European Commission President Ursula von der Leyen said on Wednesday, leaving no uncertainty about her verdict on Trump’s relationship with the bloc.
“This new dawn in America is the moment we’ve been waiting for so long. Europe is ready for a new start with our oldest and most trusted partner,” she said in the European Parliament in Brussels, Belgium.
Von der Leyen said Biden’s inauguration would “be a message of healing for a deeply divided nation and it will be a message of hope for a world that is waiting for the US to be back in the circle of like-minded states.”
On Twitter, she added: “The United States is back. And Europe stands ready. To reconnect with an old and trusted partner, to breathe new life into our cherished alliance.”
“It’s time to bring back conviction & common sense and rejuvenate our EU-US relationship,” Charles Michel, President of the European Council, added later.
Biden has signaled a warmer partnership with Europe than Trump, who frequently criticized the EU on trade during his administration. His attacks on some European leaders led to frosty scenes at a number of summits.
Hours before the inauguration, Beijing expressed hope that Biden would “look at China rationally and objectively” to repair “serious damage” in bilateral ties caused by the Trump presidency.
“In the past four years, the US administration has made fundamental mistakes in its strategic perception of China … interfering in China’s internal affairs, suppressing and smearing China, and causing serious damage to China-US relations,” foreign ministry spokeswoman Hua Chunying said at a press briefing Wednesday.
The Biden administration should, Hua said, “look at China rationally and objectively, meet China halfway and, in the spirit of mutual respect, equality and mutual benefit, push China-US relations back to the right track of healthy and stable development as soon as possible.”
“If the new US administration can adopt a more rational and responsible attitude in formulating its foreign policy, I think it will be warmly welcomed by everyone in the international community,” she added.
Russia said it hoped for a “more constructive” relationship between the US and Moscow as Biden took office.
The Russian Foreign Ministry said in a statement on Wednesday that it wanted to extend the landmark Strategic Arms Reduction Treaty (New START) with the United States for a maximum stipulated five-year period.
The US-Russia arms treaty is currently due to expire just 16 days after Inauguration day.
“We consider it possible to prolong it only in the form in which the Agreement was signed and without any preconditions. An extension for the maximum five-year term stipulated in the Agreement looks preferable,” the Foreign Ministry said in a statement released just after Biden was sworn in.
The statement added that Moscow hoped for a “a more constructive approach in the dialogue with Russia and will take into account all the points mentioned above.”
It concluded: “For our part, we are ready for such work on the principles of equality and mutual consideration of interests,” the statement concluded.
Biden has previously signaled that he intends to take a tough line against potential Russian aggression.
Antony Blinken, Biden’s pick to lead the State Department, said Tuesday that Biden intends to seek an extension of the New START Treaty, but suggested he has not made a decision on the length of the extension.
Iran’s President, Hassan Rouhani, called on Biden to return to the 2015 nuclear deal and lift US sanctions on Iran, overturning a key part of Trump’s foreign policy program.
“The ball is in the US’ court now. If Washington returns to Iran’s 2015 nuclear deal, we will also fully respect our commitments under the pact,” Rouhani said in a televised cabinet meeting.
He also launched a scathing attack on the outgoing President. A “tyrant’s era came to an end and today is the final day of his ominous reign,” Rouhani said of Trump’s departure. “Someone for whom all of his four years bore no fruit other than injustice and corruption and causing problems for his own people and the world.”
Biden has said he plans to return to the nuclear deal with Iran, which was signed when he was Barack Obama’s Vice President. Biden’s national security aides have suggested they would like further negotiations on Iran’s ballistic missile capabilities, though Rouhani has said the missile program is non-negotiable.
The German President said he was relieved that Biden would be sworn in Wednesday, calling it “a good day for democracy.”
“In the United States, (democracy) held up against a lot of pressure,” Frank Walter Steinmeier said in a statement.
“Despite internal hostility, America’s institutions have proven strong — election workers, governors, judiciary, and Congress,” he said. “I am relieved that Joe Biden is sworn in as President today and coming into the White House. I know that this feeling is shared by many people in Germany.”
Steinmeier also warned against the populist brand of politics that Trump embraced. “Despite all the joy we have about today, we must not forget that populism has seduced even the most powerful democracy in the world,” he said. “We must resolutely oppose polarization, protect and strengthen the public space of our democracies, and shape politics on the basis of reason and facts.”
French President Emmanuel Macron marked the day with a tweet welcoming the US back into the Paris climate agreement.
“We are together. We will be stronger to face the challenges of our time. Stronger to build our future. Stronger to protect our planet. Welcome back to the Paris Agreement,” Macron said.
Biden will sign a slate of executive actions in the Oval Office on Wednesday, including one to rejoin the Paris Agreement.
He will sign an instrument that will be deposited with the United Nations later on Wednesday. The US will officially become party to the agreement in 30 days.
The US left the agreement in November 2020 under the Trump administration.
British Prime Minister Boris Johnson said he was looking forward to a close relationship with Biden’s administration.
“In our fight against Covid and across climate change, defence, security and in promoting and defending democracy, our goals are the same and our nations will work hand in hand to achieve them,” Johnson said in a statement Tuesday.
Johnson warmly welcomed Trump on his visits to the UK, with Trump once claiming that the Prime Minister was nicknamed “Britain Trump.” But the outgoing US leader was unpopular among Britons, and Johnson will be keen to secure a post-Brexit trade deal with Biden.
The new President could end up making two trips to the UK in 2021, with Johnson saying he looks forward to welcoming him to the G7 summit and to the hotly anticipated 2021 United Nations Climate Change Conference in Glasgow, Scotland. “Only through international cooperation can we truly overcome the shared challenges which we face,” Johnson said on Tuesday.
Scotland’s First Minister, Nicola Sturgeon, was more blunt in her remarks in the Scottish Parliament on Wednesday. Sturgeon wished Biden and Kamala Harris well, adding: “I’m sure many of us across the chamber and across Scotland will be very happy to say cheerio to Donald Trump today.”
“I think ‘don’t haste ye back’ might be the perfect rejoinder to him,” she added.
Shortly after Biden swearing-in, Canadian leader Justin Trudeau said he would work with the new US President “to make our countries safer, more prosperous, and more resilient.”
“Canada and the United States enjoy one of the most unique relationships in the world, built on a shared commitment to democratic values, common interests, and strong economic and security ties,” he said. “Our two countries are more than neighbours — we are close friends, partners, and allies.
“Canada and the United States have worked side-by-side to tackle some of the greatest challenges we have faced in our history,” Trudeau also said.
Mexico’s President, Andrés Manuel López Obrador, wished Biden well ahead of his inauguration on Wednesday.
During his daily briefing, López Obrador outlined three themes as key areas of the bilateral relationship with the US. “Those three themes are very important: pandemic, economic recovery and migration,” he said.
López Obrador also said Biden should take steps to settle the immigration status of Mexicans working in the US.
“Today a true friend of Ireland Joe Biden became the 46th President of the USA,” Irish Prime Minister Micheál Martin said. “As he said in his speech, it is a day of history and hope and I look forward to forging ever closer ties between our two great nations.”
“Also, a historic day as Kamala Harris is sworn in as the first woman Vice President of the USA. I wish her and President Biden every success in meeting the challenges ahead,” he added.
The Vatican published Pope Francis’ message to President Joe Biden, the United States’ second Catholic President, following his inauguration.
“On the occasion of your inauguration as the forty-sixth President of the United States of America, I extend cordial good wishes and the assurance of my prayers that Almighty God will grant you wisdom and strength in the exercise of your high office,” the message says.
“Under your leadership, may the American people continue to draw strength from the lofty political, ethical and religious values that have inspired the nation since its founding.
“At a time when the grave crises facing our human family call for farsighted and united responses, I pray that your decisions will be guided by a concern for building a society marked by authentic justice and freedom, together with unfailing respect for the rights and dignity of every person, especially the poor, the vulnerable and those who have no voice,” the Pope wrote.
In a series of tweets, Indian Prime Minister Narendra Modi offered his “warmest congratulations” to US President Joe Biden. Modi said he looks forward to working with Biden and “to strengthen (the) India-US strategic partnership.”
“The India-US partnership is based on shared values,” he wrote. “We have a substantial and multifaceted bilateral agenda, growing economic engagement and vibrant people to people linkages. Committed to working with President @JoeBiden to take the India-US partnership to even greater heights.”
Congratulating President Joe Biden and Vice President Kamala Harris on what he called their “historic inauguration,” Israel’s Prime Minister Benjamin Netanyahu reminded the new US leader he sees Iran as their number one challenge to confront.
“President Biden, you and I have had a warm personal friendship going back many decades. I look forward to working with you to further strengthen the US-Israel alliance, to continue expanding peace between Israel and the Arab world and to confront common challenges, chief among them the threat posed by Iran,” Netanyahu said in a video statement.
NATO’s Secretary General Jens Stoltenberg called Biden’s inauguration “the start of a new chapter for the transatlantic Alliance.”
“U.S. leadership remains essential as we work together to protect our democracies, our values and the rules-based international order,” he said.
“NATO Allies need to stand together to address the security consequences of the rise of China, the threat of terrorism, including in Afghanistan and Iraq, and a more assertive Russia.”
CNN’s Ramin Mostaghim, Eleanor Pickston, Luke McGee and Stephanie Halasz contributed.