And Prince Charles looked swell as he walked Markle partway down the aisle.
But the American guests were scene-stealers, including tennis star Serena Williams, the TV personality Oprah Winfrey - and the Clooneys, George and Amal, in the A-list seats across from the royal family in the Quire beside the choir (better get that right).
The 600 people inside St. George's Chapel dutifully stood at the end and belted out the national anthem - "God save our gracious queen, long live our noble queen!" - as the queen herself accepted the honours.
Her Majesty was frocked in a delicately flared dress of lime, lemon, purple silk - a spring-season Popsicle - which the 92-year-old monarch managed to pull off.
Between the ancient music, the Bach and Handel, the wedding guests listened to Karen Gibson and the Kingdom Choir singing in swaying gospel style the classic Stand By Me, by Ben E. King, and once upon a time covered by John Lennon.
Then there was the address, the rousing wake-up-and-praise-Jesus sermon by Bishop Michael Curry, the first African-American to preside over the Episcopal Church.
Within minutes, Curry was trending on Twitter.
His sermon, on the power of love, was heartfelt, theatrical, folksy. Not everyone in Britain got it. The BBC's cutaways to the perplexed faces of some of the royals were priceless. But it was among the most memorable moments.
Speaking directly to Harry and Meghan, who were seated and holding hands, Curry began by invoking the Rev. Martin Luther King Jr. "There's power in love. Do not underestimate it. Anyone who has ever fallen in love knows what I mean," he said at the beginning.
"Love can help and heal when nothing else can," Curry said. "Love can lift up and liberate for living when nothing else will."
Near the end of his remarks, Curry got a laugh when he said, "With this, I'll sit down. We got to get y'all married."
Markle arrived for the service in a 1950 Rolls-Royce Phantom IV, with her mother, Doria Ragland, by her side. (One of the sideshows of the past week was whether Markle's 73-year-old father was well enough to walk his daughter down the aisle as planned. He was not.)
Markle emerged and the dress was revealed. She wore a simple, elegant wedding gown. Fashion reporters called it a confident dress. It was not a sexy dress, but it was a beautiful dress, an assured statement.
It was designed by British designer Clare Waight Keller, the first female artistic director at the French fashion house Givenchy. Kensington Palace reported that Markle and Keller worked closely together on the design.
From Kensington Palace: "The focus of the dress is the graphic open bateau neckline that gracefully frames the shoulders and emphasizes the slender sculpted waist. The lines of the dress extend towards the back where the train flows in soft round folds cushioned by an underskirt in triple silk organza. The slim three-quarter sleeves add a note of refined modernity."
Before his bride's arrival, the red-bearded Prince Harry marched with a happy gait toward the chapel's West Door, alongside his best man, his older brother and the second in line to the throne, Prince William, Duke of Cambridge.
Both Harry and William wore the frock coat uniforms of the Blues and Royals regiment. Bespoke, cut and sewn by hand, Harry was wearing his aviator wings and a medal honoring his service as an Apache helicopter pilot in Afghanistan.
Harry appeared just a little nervous.
Meghan was camera-ready. She smiled and hit her marks, like the seasoned professional she is.
After the "I dos," the couple emerged and boarded an Ascot Landau carriage, pulled by four Windsor Grey horses. The horses were lively - and they trotted through the streets of Windsor town in a fast 25-minute loop that revved up the crowds, though the speed of the procession disappointed some who wanted a longer look after waiting for hours.
"It was spectacular," Jayne Ralph, 50, a retail manager from Vancouver, said of the moment the newlyweds passed by. She noted that it was quick, just a few seconds, and suggested that because some people had slept outside overnight, it would have been nice if other royals could have driven by, too, and offered a wee wave.
Ralph also couldn't stream the wedding ceremony over her phone - as all journalists in the city can attest, the WiFi and cellular coverage was patchy at best - but she heard the ceremony piped over loudspeakers. Many people sang along to "Stand by Me." "Being here with the crowds, and singing - it was quite moving," she said.
Meanwhile, within the castle walls, the guests who had listened on loudspeakers reflected on the service. Yvonne Roberts, 74, and her daughter Lesley Roberts, 50, said they liked it very much.
"It wasn't traditional, but it was obvious it was what they wanted to do. And it's their day," Lesley said.
Yvonne said, "you just want them to be happy, don't you?"
The pair sang along with the well-known hymns. "I couldn't hear Meghan's vows," said Yvonne, "because of the airplanes." (Windsor Castle is on Heathrow Airport's flight path.)
She added: "But I think I said 'amen' at the right moments."
