Kennedy, who would have turned 83 on Thursday, was assassinated in 1968 while campaigning for the Democratic presidential nomination.
The senator "was about wanting to make life better for others," said Gov. David Paterson, who handed Ethel Kennedy a framed copy of the bill he signed renaming the bridge.
Paterson reminded the audience that in 1968, Kennedy had predicted that it would take 40 years for a black president to be elected. Some of the other speakers likened President-elect Barack Obama's ideals to Kennedy's.
Robert F. Kennedy Jr. said the bridge was an appropriate tribute because his father "was about bridging all the differences."
The bridge, which connects Manhattan, the Bronx and Queens, serves one of the largest number of ethnic groups living in the same city. The Democratic club from multiethnic Astoria, Queens, was the first to endorse Kennedy when he ran for the Senate.
Kennedy "operated on a grand scale," said Mayor Michael Bloomberg. "He united us as New Yorkers and as Americans. America would not be the country it is without Robert F. Kennedy and all the Kennedys."
To mark the renaming of the bridge, Paterson has announced a set of public school lesson plans based on the theme of social justice.
It is a partnership between the Robert F. Kennedy Center for Justice and Human Rights and the state teachers' union.
The New York Transit Museum has also unveiled a yearlong exhibit showcasing the historic bridge as well as Kennedy's life and career.
Bill Clinton remembered Kennedy's assassination as "heartbreaking. ... You had no doubt that he cared about the people he spoke of."
He said his wife, Sen. Hillary Rodham Clinton, did not attend because she was in Washington working for causes that were dear to Kennedy: making sure people had homes and jobs.
Among other dignitaries attending were former mayors David Dinkins and Ed Koch and former Gov. Hugh Carey.
The bridge opened in 1936 and is operated by the Metropolitan Transportation Authority. It is the first major public work dedicated to Kennedy in the state he represented from 1965 to 1968.
To many people around the world, it is known as a way to get to Kennedy International Airport.
