Emmanuel Macron has said a "new page of our history" has opened after he defeated far-right populist Marine Le Pen to become France's new president.
Voters delivered a resounding victory for the pro-European former investment banker, strengthening France's place as a central pillar of the EU, and he immediately vowed to "defend France and Europe".
He acknowledged divisions in society which drove people to "vote to the extreme", and said he will work for all of France.
A crowd of Macron supporters roared with delight, jubilantly waving red, white and blue tricolour flags at a victory party outside the Louvre Museum in Paris.
Ms Le Pen said she had called the 39-year-old to concede defeat after voters rejected her 'French-first' nationalism by a large margin.
Pollsters project Mr Macron won 65 per cent of the vote to make him France's youngest president in history.
Ms Le Pen's projected 35 per cent score was lower than her polling numbers earlier in the campaign, and dashed her hopes that the populist wave which swept Donald Trump into the White House would also carry her to France's presidential Elysee Palace.
Mr Macron's victory marks the third time in six months – following elections in Austria and Holland – that European voters shot down far-right populists who wanted to restore borders across Europe.
The election of a French president who championed European unity could also strengthen the EU's hand in its complex divorce proceedings with Britain.
In a statement minutes after the last polls closed on Sunday night, French prime minister Bernard Cazeneuve announced Mr Macron's victory.
"[This] testifies to the lucidity of the voters who rejected the deadly project of the extreme right," he said, adding that voters also showed they embrace the EU.
But many French voters backed Mr Macron reluctantly, not because they agree with his politics but simply to keep out Ms Le Pen and her far-right National Front.
After the most closely watched and unpredictable French presidential campaign in recent memory, many voters rejected the run-off choice altogether – pollsters project there were a record number of blank or spoiled ballots.
Mr Macron now becomes not only France's youngest president but also one of its most unlikely. Until now, modern France had been governed either by the socialists or the conservatives – but both Mr Macron and Ms Le Pen upended those political traditions.
Unknown to voters before his turbulent 2014-16 tenure as France's pro-business economy minister, Mr Macron took a giant gamble by quitting the government of outgoing Socialist president Francois Hollande to run as an independent in his first electoral campaign.
Despite her loss, Ms Le Pen's advancement to the run-off for the first time marked a breakthrough for the 48-year-old. She had placed third in the 2012 presidential vote, underscoring a growing acceptance for her fierce anti-immigration, France-first nationalism among disgruntled voters.
After conceding defeat, she immediately turned her focus to France's upcoming legislative elections in June, where Mr Macron will need a working majority to govern effectively.
"I call on all patriots to join us," she said.
"France will need you more than ever in the months ahead."
Mr Hollande congratulated Mr Macron and said his victory shows the overwhelming majority of voters rallied behind the European Union and openness to the world.
German chancellor Angela Merkel's chief of staff Peter Altmaier congratulated Mr Macron with a tweet saying: "Long live France, long live Europe!," while her chief spokesman Steffen Seibert said it is a victory "for a strong and united Europe".
European Commission president Jean-Claude Juncker said in a message to Mr Macron that it makes him "happy that the ideas that you defended of a strong and progressive Europe that protects all its citizens will be those that France will cherish under your presidency".
In a tweet, Mr Trump said: "Congratulations to Emmanuel Macron on his big win today as the next president of France. I look very much forward to working with him."
A White House statement cited Mr Macron and the French people for "their successful presidential election" and said the United States looks forward to "continuing our close relationship with the French government".
