During the service, streamed live on the Internet, Kate did not promise to "obey" William as part of her wedding vows, and he will not wear a wedding ring. Her ring is made out of Welsh gold.
When it came time to slip the ring on her finger, Prince William seemed to struggle a little as the ring appeared a tiny bit tight.
The couple looked nervous but happy and got through their vows without stumbling before they were formally declared married by the Archbishop of Canterbury Rowan Williams, the spiritual leader of the Church of England, with the words "I pronounce that they be man and wife together."
Hundreds of thousands of people crammed the flag-lined streets of London to catch a glimpse of cavalrymen in shining ornamental breastplates, groomed horses and the ornate carriages that will carry senior royal figures from the service.
The weather co-operated when it was time for the newlyweds to ride the 1902 State Landau, an open-air horse-drawn carriage, along the royal procession route to Buckingham Palace.
The couple will now attend a lunch reception for 650 guests, followed by an evening party for 300 friends and family.
"The pictures on the mugs don't do the couple justice," said 34-year-old Madeleine Senior who flew in from Australia for the big day.
Die-hard fans camped out across the street from the abbey to ensure a front-row view of the royal couple and their guests, who start filing into at the abbey via The Great North Door from 8:15 a.m. (3:15 a.m. ET) in time for the 11 a.m. start of the service.
Queen Elizabeth and Prince Philip arrived to fanfare at the abbey, Prince Charles and his wife Camilla arrived before them, Ms. Middleton's parents appeared before them.
Soccer star David Beckham and his wife Victoria - aka Posh Spice - attended, as did Chelsy Davy, Prince Harry's on-again, off-again girlfriend, and Australian swimmer Ian Thorpe also showed up.
Elton John and Canadian husband David Furnish have arrived, and so has former British Prime Minister John Major.
Another notable guest, current British Prime Minister David Cameron has reversed his decision to wear a lounge suit (what we North Ameircans would call a "suit") and instead he has gone with tradition and worn a morning suit (what we'd call "tails").
"It's a mixture of this amazing young couple, the fact they love each other, it's also the institution, the national symbolism, the monarchy, the service of the royal family," he told BBC TV.
"It's all those things and a chance to celebrate. We are quite a reserved lot, the British, but then when we go for it, we really go for it."
Some 8,000 reporters and support staff have descended on the capital to capture the occasion in words and images, and, while some question a British government estimate of a global audience of two billion, hundreds of millions certainly tuned in.
As the bells toll across the Atlantic, a number of Canadians are swapping pyjamas for pageantry to toast the couple who have not only become the ultimate celebrities, but could also one day be an important part of how this country is governed.
Some are donning their best hats and heading to public venues for the occasion while others are gathering in their living rooms with crumpets and a cup of English tea as the festivities begin.
"The atmosphere has been truly amazing, the crowd is buzzing," Canadian Jay Edmonds told Reuters as dawn broke outside Westminster Abbey on Friday. "I managed to catch just a few hours sleep in a doorway but I don't mind.
Daniel Whaley is part of a group of 45 Canucks who travelled to London for the festivities and considers witnessing the wedding a once-in-a-lifetime experience.
"This is a monumental event that will go down in history. It's also the future king and queen of Canada that are getting married," says the 19-year-old University of Winnipeg student who is also co-chairman of the Monarchist Youth League of Canada.
"It's electrifying ...you're seeing the future of a historic institution in a flash."