The actress, 48, and the political activist, 60, became engaged in May 2014.
"It's fun that the two families are coming together," she told PEOPLE in June. "It's very sweet that way. I come from a big family and the Kennedys are a big family. It feels natural. It feels fun."
Hines wore a white strapless tea-length gown by Romona Keveza for the ceremony, and Kennedy slipped a Neil Lane wedding ring on her finger, which complemented her engagement ring, also designed by the jeweler.
The wedding took place during the family's annual reunion and besides many Kennedys, other guests, according to PEOPLE's sources, included Larry David, Julia Louis-Dreyfus, Sen. Ed Markey, Kevin Nealon and Ed Begley Jr.
The couple wed during a "casual ceremony," before celebrating with a reception "at Teddy's place" on the family compound, Kennedy told The New York Times.
Their union comes after the two were introduced twice by David at a ski resort in Deer Valley, Utah, followed up by a third meeting in Aspen, Colorado. "I was separated at the time, and Cheryl was still married," Kennedy says.
Their friendship eventually progressed "slowly at first and then all at once" to a romantic relationship. "She has as much integrity as anyone I've ever seen," Kennedy says of his new wife.
It's the second marriage for Hines, who has a daughter, Catherine Rose, 10, with her former husband. It's the third marriage for Kennedy. He has two children with his first wife, Emily Black, and four children with his second wife, Mary Richardson Kennedy, who committed suicide in May 2012, at age 52.
And although the couple had planned to elope with their children, Hines tells The Times that they couldn't leave their mothers out of the celebration – and from there the guest list just kept growing.
"The next thing we knew, it was a wedding," she says.
The Curb Your Enthusiasm star is looking forward to being Mrs. Kennedy. "It feels great because you know you are going to be with the person you really like to be with for a very long time," she told PEOPLE last month. "And that's a great feeling."
Stew Milne / AP; FameFlynet