Cory Booker, the charismatic mayor of Newark, is now a member of the U.S. Senate from New Jersey after winning a special election on Wednesday.
The Democrat, heavily favored in polls, defeated conservative Republican Steve Lonegan. Booker had an 11-point lead with the vote 90 percent counted.
Booker, 44, spoke to supporters in Newark and thanked them for turning out to vote against the backdrop of the 16-day government shutdown.
"You didn't just vote, you believed that your vote and choice mattered," he said. "It would have been easy to listen to this frustrating negativity and stay home."
"But here in New Jersey, more than a million people rejected cynicism and came out on a Wednesday, in the middle of October, to fight the cynicism."
Booker is the first black U.S. Senator from New Jersey and joins Republican Tim Scott of South Carolina as the nation's only two black U.S. senators.
He will fill the U.S. Senate seat held by Democrat Frank Lautenberg, who died in June at age 89. Booker had planned to run for this seat in 2014.
Lautenberg's passing prompted a special election, however, and Gov. Chris Christie, who is running for re-election now, set the October 16 date.
Christie, like Booker a possible White House contender in 2016 or down the road, could have scheduled the Senate race for Election Day, November 5.
Democrats said was avoiding being on the ballot with Booker, who could attract Democratic turnout. He said he wanted to fill the Senate vacancy ASAP.
Booker, a Rhodes scholar and Yale Law School graduate, rocketed to fame in the state's largest city, which has long struggled with poverty and crime.
Booker is known to rub shoulders with celebrities and is a near-constant presence on Twitter, where he recently befriended stripper Lynsie Lee.
Newark received a $100 million gift to its schools from Facebook founder Mark Zuckerberg, who said he had met Booker and was impressed by his plans.
A bachelor, Booker has long been rumored as a future presidential candidate. Whether that happens or not, he's one step closer to it being possible now.