Emmanuel Macron has insisted that 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% of the vote to make him France's youngest president in history.
Ms Le Pen's projected 35% 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.
At a victory rally, Mr Macron said that France is facing an "immense task" to rebuild European unity, fix the economy and ensure security against extremist threats.
Speaking to thousands of supporters from the Louvre Museum's courtyard, Mr Macron said that Europe and the world are "watching us" and "waiting for us to defend the spirit of the Enlightenment, threatened in so many places".
Mr Macron, who has never held public office and just founded his political movement a year ago, said: "Everyone said it was impossible. But they didn't know France".
He also promised to work to unify France after a bruising presidential campaign and serve the country "with love".
His wife Brigitte then came up on stage with him, and she kissed his hand and waved to the crowd.
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.