The second-in-line to the British throne and his longterm sweetheart became husband and wife in a traditional ceremony at London's Westminster Abbey.
The couple, who began dating in 2003 after they met while studying at university, married in front of a hushed congregation of 1,900 guests, including Britain's royal family, 50 foreign heads of state from across the world, and an array of close friends and showbiz pals.
Outside the abbey, an estimated one million royal-watchers gathered on the streets of London to join in the celebrations. Two billion people are thought to have watched the event live on television around the world.
The groom, wearing the famous red tunic of the Irish Guards and a garter sash of the Royal Air Force, and his best man, brother Prince Harry - in his Blues & Royals army officer's uniform - arrived at the venue in a two-car convoy at 10.18am local time, some 25 minutes ahead of their father, Charles, Prince of Wales and his wife Camilla, Duchess of Cornwall, and 30 minutes before Queen Elizabeth II and Prince Philip, Duke of Edinburgh.
The bride arrived at the venue by chauffeur-driven Rolls-Royce Phantom VI, with her father Michael, at 11am.
Wearing a dress by Sarah Burton for Alexander McQueen, and the late Queen Mother's halo tiara, she walked up the aisle to the coronation anthem, "I was glad", trailed by her Maid of Honour - sister Philippa Middleton - bridesmaids Lady Louise Windsor, seven, The Honourable Margarita Armstrong-Jones, eight, and three year olds Eliza Lopes and Grace van Cutsem, along with page boys William Lowther-Pinkerton, 10, and Tom Pettifer, eight.
The royal couple chose the Series One (1966) Book of Common Prayer ceremony, and the occasion was soundtracked by classical compositions by Elgar, Britten and Vaughan Williams, as well as the hymns Jerusalem and Guide me, O Thou Great Redeemer, and the English melody Greensleeves.
During the service, conducted by the Archbishop of Canterbury, Rowan Williams, the couple said "I will", vowing to "love, comfort, honour and keep" each other, as the official witnesses - Prince William's father and stepmother, Prince Harry, the bride's parents Carole and Michael Middleton, her sister Philippa and brother James - looked on.
James Middleton then gave The Lesson, reading Romans 12: 1-2, 9-18 before an address by the Bishop of London, the Right Reverend Dr Richard John Carew Chartres, a recital of the Lord's Prayer, and the blessing of the marriage by the Dean of Westminster. The 50-minute ceremony was concluded with a rendition of the National Anthem and the signing of the marriage register.
As the newlyweds - now officially the Duke and Duchess of Cambridge - left the abbey hand-in-hand to be greeted by thousands of cheering, flag-waving fans, two groups of 12 military personnel lined their route as they headed to the horse-drawn 1902 State Landau carriage.
The open-top carriage - escorted by the Household Cavalry and followed by the Queen's procession with a sovereign's escort - will then make its way along Parliament Square and Whitehall, through Horse Guards Arch into Horse Guards Parade and then along The Mall to Buckingham Palace.
Tens of thousands of onlookers lined the entire route, cheering, applauding, waving flags, and shouting their best wishes to the beaming couple, who responded by smiling and waving at the assembled crowds.
On arrival at the palace, the band of the Welsh Guards will play the British National Anthem before the royal couple is expected to appear with Queen Elizabeth II on the palace balcony to greet their adoring public. A fly-past by the Royal Air Force and Battle of Britain Memorial Flight will take place before the Queen hosts a private lunchtime reception for selected guests.
On Friday evening, the groom's father Charles will host a private dinner at Buckingham Palace before the newlyweds relax with 650 family and friends.