When Booker is sworn in, the Democratic Caucus will once again hold a 55-45 advantage over the GOP Conference. Booker will fill the seat once held by Frank Lautenberg, a long-serving Democratic senator who died in June. Gov. Chris Christie appointed fellow Republican Jeff Chiesa to be Lautenberg's interim replacement.
Booker, 44, will become the chamber's second African American member along with Sen. Tim Scott (R-S.C.).
The Democrat will enter the Senate having already achieved celebrity status. A regular on cable news programs and Sunday morning news shows with more than 1.4 million followers on Twitter, Booker has cultivated a profile that extends well beyond New Jersey.
He could fill a void in the Senate. While there are a handful of freshman Republican senators with growing national profiles like Sens. Ted Cruz (Tex.), Rand Paul (Ky.) and Marco Rubio (Fla.), there is a dearth of new Democratic senators eager for a spotlight.
Booker won comfortably Wednesday despite running a lackluster campaign. He was veered off message by tweets he sent to an Oregon stripper and questions about whether or not a drug dealer he cited often in early political speeches was real or not.
His once wide lead narrowed in the closing weeks of the race. Lonegan sought to seize the opening, but was limited by his political profile. A conservative Republican who campaigned with Paul and Sarah Palin, Lonegan's views were out of step with most voters in the deep blue state.
Booker also had to deal with personal tragedy during the campaign. His father passed away last week, prompting him to take some time away from campaigning.
Elections are typically held on Tuesdays, but New Jersey opted for a rare Wednesday vote at the order of Christie, who said he wanted New Jerseyans to elect a a senator as soon as possible under state law. Critics suggested Christie was simply looking out for himself, and didn't want the popular Booker to appear on the same ballot as him next month, for fear a coattail effect might boost the governor's Democratic opponent.
Updated at 10:40 p.m.