But he also played his limited hand with great skill from the beginning, outmaneuvering his elders. First, he wisely renounced the man who had given him his break, the deeply unpopular Socialist president François Hollande, quitting his post as economy minister in Mr. Hollande’s government before it was too late. Then, he refused to take part in the Socialist Party primary in January, rightly judging that party activists would dominate and choose a far-left candidate on the fringes, who would then be devoured by Mr. Mélenchon — exactly what happened.
Mr. Macron’s final correct bet was that French voters, like those elsewhere, were disgusted by the mainstream parties, having judged the policy prescriptions of both the establishment right and left as failures in dealing with France’s multiple ills. He positioned himself in the center, drawing on left and right, balancing protection of the French welfare state with mild encouragement for business, in an attempt to break through France’s employment and productivity stagnation.
But Mr. Macron’s pro-market views stirred much opposition. Mr. Mélenchon not only refused to endorse him, but also encouraged the idea that Mr. Macron and Ms. Le Pen were equivalent menaces — a calculation endorsed by many far-left voters. Nearly half the first-round electorate voted for candidates hostile to the free market and to capitalism. Even if they voted for Mr. Macron on Sunday to save the country from Ms. Le Pen, they did so without enthusiasm.
Some of the antipathy sprang from his hermetic persona, as a caricature of the elite-educated, know-it-all technocrats, perpetually encased in a dark suit, who have guided France for much its postwar history, usually from behind the scenes, and whose record is mixed.
“He’s not someone I feel a lot of conviction for,” said Thomas Goldschmidt, a 26-year-old architectural firm employee in Paris who voted for Mr. Macron after supporting the Socialist Benoît Hamon in the first round. “He’s someone who raises a lot of questions. It’s a vision of society that is too business-friendly,” Mr. Goldschmidt said. “It’s this whole idea of making working life more uncertain. We just can’t bet on it, that everyone out there can be an entrepreneur. Society isn’t built like that.”
Mr. Macron seems aware that his large victory isn’t a large mandate, that the pressure is now on to ensure that France’s reprieve from the National Front is not just a temporary one. “If I fail to solve” France’s problems “or fail to offer a solid start to solving them, in five years it will be even worse,” he told the left-wing news website Mediapart on Friday night. “What nourishes the National Front will be even more virulent,” he added.
Without an established party behind him, Mr. Macron’s most immediate hurdle will be in June’s legislative elections for France’s Parliament. He has promised to field candidates in all 577 parliamentary districts, but whether he can do so is unclear. Nor is it clear how many Socialists will support his program.
The National Front could win as many as 100 seats in the new Parliament, according to some analyses, making it a formidable opposition party. Indeed, even as Ms. Le Pen was soundly defeated on Sunday, she still managed a showing that not too long ago would have been unthinkable. And in her concession, she made it clear that she was already looking toward the parliamentary elections, and the future.
Then there is the potential opposition represented by Mr. Mélenchon, who won in some of France’s biggest cities — Marseille, Toulouse and Lille — and is already claiming the mantle of Mr. Macron’s principal opponent on the left. His voters, as much as Ms. Le Pen’s, do not trust Mr. Macron.
Mr. Macron, in his uncharacteristically brief and sober victory speech on Sunday night, recognized that he had many people to win over.
“My responsibility will be to unite all the women and men ready to take on the tremendous challenges which are waiting for us, and to act,” Mr. Macron said. “I will fight with all my power against the divisions that undermine us, and which are tearing us apart.”