The ceremony started late after guests continued arriving up to the last minute.
The stars turned out in force for Saturday's lavish ceremony, rumoured to have cost £1.2m ($1.7m), in the Grand Ballroom of the Plaza Hotel.
The couple and other star guests were already inside the hotel, where the wedding party took over 130 rooms.
The guests included actress Goldie Hawn and Zeta Jones' ex-lover, Simply Red star Mick Hucknall, singer Art Garfunkel and United Nations Secretary-General Kofi Annan.
Many turned up in limousines, stepping out under a fluttering Welsh flag and Stars and Stripes outside the hotel entrance.
The ceremony started late after guests continued arriving up to the last minute.
Producer Quincy Jones, director Oliver Stone, and movie stars Danny De Vito, Ellen Barkin and James Woods were among those who got there just before the publicised 1900 (0000GMT) start time.
Kirk Douglas, the father of the groom, gave his blessing to the nuptials.
"I'd marry her myself, but my wife won't let me," said the star of classic films such as Spartacus and Paths of Glory.
His son reportedly paid for his new bride's family - including 85-year-old grandmother and namesake Zeta - to be flown over to New York on a private jet.
The ceremony itself was shrouded in secrecy as a result of an exclusive picture deal signed with celebrity magazine OK!
The couple were last seen in public on Friday, posing for pictures as they arrived for a wedding rehearsal at the upmarket Russian Tea Rooms.
Some details are known about the wedding.
The couple's three-month-old baby Dylan watched from his grandmother's arms, while Douglas's 21-year-old son, Cameron, from his first marriage, acted as best man.
Guests were asked not to give presents but to donate money instead to a fund set up for their baby.
The wedding dress is rumoured to have cost more than £100,000.
It was designed by David Emanuel, co-creator of Diana, Princess of Wales's wedding gown.
The actress's ring, which includes a Celtic motif, was bought from a tiny family jeweller in the west Wales coastal town of Aberystwyth.
After the ceremony guests tucked into a seven-course meal with New England clam chowder, foie gras and lobster plus roasted Welsh lamb on the menu.
Desserts offered were cheesecake, apple pie or a cheese board - including Welsh Caerphilly.
The wedding is the culmination of a 20-month romance between one of Hollywood's elder statesmen and an actress who finally broke into the celebrity A-list after years of effort.
The couple, who share the same 25 September birthday, met at a film festival in France in August 1998.
Douglas' infamous chat-up line that first night was: "I want to be the father of your children."
They began dating in March 1999 and, after much speculation, got engaged last New Year's Eve.
He had to wait before he could father her first child, however.
From the outset Michael and Catherine made the effort to return to her native Wales.
He claimed to be enamoured by the people and the countryside, but described the Welsh weather as "brutal".
There were suggestions the wedding may have taken place in south Wales, with Majorca - where Douglas also has a home - Scotland and Santa Barbara in California other possibilities.
But two months ago it was finally revealed the couple had chosen New York.
Not that Zeta Jones' humble birthplace, the seaside area of The Mumbles in Swansea, was going to miss out on the big day.
Flags, bunting and a special banner were hung out from shops and a congratulatory fax was sent direct to the couple's hotel.