(Mel Evans/AP Photo)

After a sped-up race for U.S. Senate, Newark Mayor Cory Booker, a Democrat, beat Republican Steve Lonegan, a tea party conservative and former mayor of Bogota, N.J., according to the Associated Press.

With 99.3 percent of precincts reporting, Booker beat Lonegan 54 percent to 44 percent.

Booker prevailed after an unusual four-month race to fill the Senate seat vacated by the death of Sen. Frank Lautenberg, a fellow Democrat, in June.

Booker, 44, will serve out the last 15 months of Lautenberg's term, and will need to run in 2014 for a chance at serving a full six-year term beyond that.

Booker led Lonegan, 57, by more than 30 points as recently as September, but a Monmouth University poll released this week showed a gap narrowed to 10 points.

John Weingart, the associate director of the Eagleton Institute of Politics at Rutgers University, told ABC News, "Cory Booker has followed a very unlikely path to be a national celebrity and rising political star."

"To be a mayor of one of the poorest cities in New Jersey and, perhaps, the country would not normally be seen as a path to U.S. Senate and so, stepping back a little bit, that's remarkable," Weingart said. "He is going to be arriving in the Senate much the same way … that Elizabeth Warren, Barack Obama and Hillary Clinton did - nationally known from the first moment in the Senate. And he will have to navigate the demand and the expectations of having a national constituency while learning the mechanics of the Senate and becoming a senator. … He will have to navigate the reality of being a brand-new junior senator, plus being a national celebrity."

Booker is not only the first African-American U.S. senator from New Jersey, he is the first African-American to be nominated by a major party for a statewide office in New Jersey.

The Twitter-savvy senator elect quickly thanked the state on the social media site writing, "Thank you so much, New Jersey. I'm proud to be your senator-elect"

In his victory speech he told supporters he would make the U.S. Senate "more accessible to all of us."

"I will bring more voices to the voiceless, and I will be dogged, determined, relentless and unfaltering in my sense of service to all of New Jersey," Booker said, adding in an emotional moment that it had been a difficult week for him. His father Cary passed away last Thursday after suffering a stroke. He said his father was "here in spirit."

"My dad and my mom taught me," Booker said. "You can't have extraordinary success without personally putting forward extraordinary effort."

Throughout the campaign, Lonegan, the former director of the New Jersey chapter of Americans for Prosperity, and his backers tried to portray Booker as more interested in Hollywood celebrity and engaging with his Twitter followers than willing to work on improving Newark, consistently pointing out his famous friends and Newark's still-high crime rate.

Booker backers - including President Barack Obama, who sent out a video message in support of his friend this week - praised him during this time of intense partisanship in Washington D.C., as well as the shutdown showdown, as someone who would work across the aisle while Lonegan was more likely to increase the partisanship at the Capitol.

"Much of his political persona and, certainly, his campaign, has been about not being defined by partisanship and … the idea of forging alliances across party lines on any significant issues right now seems daunting," Weingart said. "But that is what he has pledged to do."

Obama's video message, released on Monday, said, "Cory Booker has spent his entire life bringing people with different perspectives together, regardless of party, to take on tough challenges."

"Take it from me," President Obama said. "Now more than ever before, that's the kind of leader we need in the Senate."

Booker was elected on the same evening as it looked like the impasse over funding the government and raising the federal debt ceiling would finally end in Washington, D.C., re-opening the government after 16 days and removing the threat of default from the country.

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Weingart noted that today, of all days, "If you were a Democrat, you couldn't pick a better day in the last 10 years to be campaigning against Steve Lonegan with what's going on nationally and the dysfunction in Washington."

"It's Ted Cruz who Lonegan has explicitly said he wants to emulate," Weingart said.

Lonegan had his own high-profile backers. Sen. Rand Paul, R-Ky., and Texas Gov. Rick Perry, another Republican, both made the trip to New Jersey to campaign for him. And former Alaska Gov. Sarah Palin joined the Tea Party Express at a 2,000-person rally in the Garden State on Saturday and urged her supporters on Tuesday to "make history" by voting for Lonegan.

The unusual election date was set by New Jersey's Republican governor, Chris Christie, after Lautenberg's death. He said he chose the date because he wanted to fill the seat as soon as possible, but his political opponents claimed he did not want to share the ballot with the popular Booker.

Christie's gubernatorial election is next month. He is facing off against Democratic state Sen. Barbara Buono and leads by almost 30 points in most polls.