Markle entered the chapel unescorted, dressed in a flowing white gown created by British designer Clare Waight Keller and wearing a veil and diamond tiara.
In a ceremony that combined modernity and the ancient rituals of a royal house that dates back to 1066, Prince Charles, heir to the throne and Harry’s father, accompanied Markle to the altar from the middle of the chapel.
Harry, looking nervous, appeared to say: “Thanks, Pa” to Charles and “You look amazing!” to his bride. Markle’s mother, Doria Ragland, 61, shed tears. A gospel choir sang American soul singer Ben E King’s 1960s hit “Stand by me”.
“There’s power in love,” black US bishop Michael Bruce Curry told a congregation that included Queen Elizabeth, senior royals and celebrities such as US mogul Oprah Winfrey, singer Elton John and former soccer star David Beckham.
“Do not underestimate it. Anyone who has ever fallen in love knows what I mean,” Curry told the congregation in a powerful, energetic address that quoted US civil rights campaigner Martin Luther King.
The newlyweds will be known as the Duke and Duchess of Sussex, putting them in the senior ranks of British royalty.
But alongside tradition, there was innovation, by British royal standards. Markle, 36, did not vow to obey her husband; Harry, three years her junior, will wear a wedding ring – unlike other senior male royals.
The world’s media have been gripped by the occasion, and television channels beamed the ceremony across the world.
To some Britons, the wedding of a senior member of the royal family to a divorcee whose mother is African-American and father is white embodied a modern Britain where race or background are no bar to even the most elite and traditional of institutions.
To others, it was an irrelevance or mild distraction from the schism of Brexit, which has deeply divided the United Kingdom; polls suggested that most Britons would not bother tuning in.
But in Windsor, tens of thousands of fans lined the Long Walk promenade leading to the castle, waving British flags and cheering as Markle’s Rolls-Royce limousine drove past.
Air traffic controllers for the nearby Heathrow Airport, one of the world’s busiest, closed the airspace over Windsor for the 15 minutes before the ceremony.
Hours before, Elizabeth had bestowed the title of Duke of Sussex on her grandson, a step that meant the actress, star of the TV drama “Suits”, became a duchess when she married Harry.
(The story has been published in an arrangement with Reuters. The story has been edited for length)