At a ceremony in Windsor, west of London, Elton exchanged vows with filmmaker David Furnish in the same 17th-century Guildhall venue where Prince Charles wedded Camilla Parker Bowles last April.
Fans of the 58-year-old Elton filled the streets of the well-heeled town, while others followed the action on live television.
The slightly rotund Elton sported a pair of coloured glasses and a salmon-coloured tie as he arrived in a black Roll-Royce limousine with his 43-year-old Canadian mate, smiling and waving to the crowd.
The normally flamboyant pair surprised some pundits by wearing traditional black morning suits. The civil partnership ceremony was a small, private affair, attended by a handful of friends and with the couple's parents acting as witnesses.
However in true Elton style he will host up to 700 guests at a lavish evening party on his nearby estate, including former Spice Girl Victoria Beckham and singer George Michael.
Among those offering congratulations was Prime Minister Tony Blair who said: "I wish him and David well, and all the other people exercising their rights under the civil partnerships law.”
He told reporters at his monthly news conference "I think it is a modern, progressive step forward for the country and I am proud we did it."
A wave of services
Up and down the country nearly 700 homosexual couples lined up to sign official papers giving them virtually the same rights as heterosexual couples in such areas as inheritance and tax.
Among the very first to take advantage of the new civil partnership legislation were three couples who simultaneously signed on the dotted line at exactly 8am (0800 GMT).
That was the moment when the register office opened for what would be a busy day in the Bohemian south coast city of Brighton, England's self-styled gay capital.
"I'm really excited! I'm very happy to be one of the first," said gay wedding planner Gino Meriano as he embraced Mike Ullett, who has became, in the eyes of the law, his partner for life.
As the couple of seven years walked into the marriage room, the Brighton Gay Men's Chorus sang: "You are the luckiest people in the world."
The civil partnership act came into force on December 5, having provoked little controversy. But since gay couples are also required to mark a statutory waiting period, the first ceremonies could not take place until this week.
Though most ceremonies will take place in England and Wales, the first in the United Kingdom were conducted on Monday in Northern Ireland, followed Tuesday in Scotland.