Booker, who has been mayor of Newark since 2006, defeated Republican Steve Lonegan, the former mayor of Bogota, The Star-Ledger of Newark reported. Booker becomes New Jersey's first black senator and increases the Democratic advantage in the upper house to 55-46, including two independents caucusing with the majority.
In his victory speech, Booker thanked New Jersey voters and paid tribute to Lautenberg, who died in June after representing the state in the Senate for most of the past 30 years.
"Despite the cynicism and the negativity we often see on TV, despite a special election, New Jerseyans, hundreds of thousands, rejected all that and came out and voted," Booker said at a rally in the New Jersey Performing Arts Center in Newark. "But more than that, you didn't just vote, but you believed that your voice and your vote mattered. You believe that you don't have to resign yourself to what's wrong, but you can do something -- we can do something to make it right."
Lonegan conceded, saying he plans to return to the private sector. His most recent post has been state director of the conservative political action group Americans for Prosperity.
Booker led in the polls throughout the campaign, although the race tightened as the election approached. New Jersey last elected a Republican to the Senate in 1972.
Republicans got the seat for a few months when Gov. Chris Christie appointed his attorney general, Jeffrey Chiesa, to serve until the special election. Booker will have to run for a full term next year.
The off-year race attracted national attention. Vice President Joe Biden came to New Jersey to campaign for Booker, and President Barack Obama embraced him, while former Alaska Gov. Sarah Palin -- the 2008 Republican vice presidential nominee -- campaigned with Lonegan.
Democratic National Committee Chairwoman, U.S. Rep. Debbie Wasserman Schultz, released a statement saying Booker "is a champion for the middle class and ... will be a bridge builder in Washington."
"This election was a rejection of a destructive Tea Party agenda that shut down the government and threatened default on our bills," Wasserman Schultz said.
She said Booker's "arrival on Capitol Hill will mean another vote to put gridlock aside and a focus on helping the working families of New Jersey and across the country."