Prince William and Kate Middleton have kissed twice on the balcony of Buckingham Palace after their wedding service in Westminster Abbey.
They were cheered by 500,000 well-wishers who gathered outside the palace, as RAF planes flew past in honour of the new royal couple.
In the evening the pair returned to the Palace for a dinner and dance, expected to continue into the early hours.
The couple will now be known as the Duke and Duchess of Cambridge.
Police estimate a million people lined the procession route from the abbey to the palace following the wedding.
Prince William later drove his new bride back to Clarence House, following a buffet reception at Buckingham Palace, at the wheel of his father's classic blue Aston Martin, before returning to the palace in the evening.
The vehicle was decked in ribbons and balloons with "Just Wed" on the number plate.
The church service, watched by 1,900 guests, ran smoothly but the prince did struggle to place the wedding ring on the duchess's finger.
Following a long tradition, the ring has been fashioned from Welsh gold given to Prince William by the Queen.
After the couple said their vows - in which the bride did not promise to obey her husband - the Archbishop of Canterbury, the Most Reverend Dr Rowan Williams, declared: "I pronounce that they be man and wife together, in the name of the Father, and of the Son, and of the Holy Ghost. Amen."
They spent a private moment together with their families, as they signed the marriage register.
Prince William has been given the title of the Duke of Cambridge by the Queen, and Miss Middleton has become Her Royal Highness the Duchess of Cambridge on their marriage.
The duchess, who managed to keep her wedding dress a secret, wore an ivory and lace gown by Sarah Burton at Alexander McQueen. The prince wore the red tunic of an Irish Guards colonel - his most senior honorary appointment.
Among the guests at Westminster Abbey were singer-songwriter Sir Elton John and his partner David Furnish, former England rugby coach Sir Clive Woodward, and former England football captain David Beckham and his wife Victoria.
Actor Rowan Atkinson, a close friend of Prince Charles, Prince Harry's friend Chelsy Davy and film director Guy Ritchie were also there.
UK Prime Minister David Cameron and his wife Samantha, Australian prime minister Julia Gillard and former British PM Sir John Major were among the politicians present.
For those lining the route, large speakers broadcast the wedding service, and hundreds of millions of people were estimated to watch the proceedings worldwide on television.
Royal officials said the couple were involved in planning their wedding day, from the music at the ceremony to the flowers and the cake.
Inside Westminster Abbey, an avenue of trees lined the red carpet leading up to the altar.
The bride walked up the aisle to coronation anthem I Was Glad, by Sir Charles Hubert Hastings Parry, from Psalm 122. Her brother James Middleton gave the Lesson, reading Romans 12: 1-2, 9-18.
Classical compositions by Elgar, Britten and Vaughan Williams featured during the ceremony, alongside the hymn Jerusalem and the English melody Greensleeves.
A canape reception was held for 650 guests at Buckingham Palace in the afternoon.
Later, about 300 close friends and relatives were invited to a dinner and disco, hosted by Prince Charles.
The couple changed outfits for the event - Prince William was in black tie while his bride wore a strapless white satin gazar evening gown with diamante embroidered detail round the waist, by the same designer, Sarah Burton.
But the Queen and the Duke of Edinburgh left for a weekend away after hosting the lunchtime reception.
They will miss Prince Harry's best man speech and Michael Middleton's father of the bride address.
Despite predictions of showers, the weather stayed dry for the royal couple. Temperatures in London reached around 18C (64.4F) at 2pm.