French polling agencies showed the centrist candidate has triumphed over the far-right’s Marine Le Pen.
The National Front leader is forecast to have won just 35% of the votes.
Theresa May was quick to congratulate Mr Macron on his victory.
A Downing Street spokesman said: “The Prime Minister warmly congratulates President-elect Macron on his election success.
“France is one of our closest allies and we look forward to working with the new President on a wide range of shared priorities.”
Ms Le Pen, who had hoped to capitalise on the disillusionment of voters in France, said she had called Mr Macron to congratulate him on his victory just minutes after the polls came in.
French Prime Minister Bernard Cazeneuve said the vote was a rejection of the “deadly project of the extreme right”.