Booker Joins the Senate and Casts His First Vote By Courtesy of NBC Chip Somodevilla/Getty Images Booker Is Sworn In as Senator: Cory A. Booker, the former mayor of Newark, became the newest member of the Senate after he was sworn in by Vice President Joseph R. Biden Jr. WASHINGTON - Cory A. Booker, who gained celebrity as a danger-defying, super-tweeting mayor of Newark, was sworn in as New Jersey's junior United States senator on Thursday. He is the first African-American to be elected to the chamber since Barack Obama in 2004. Gabriella Demczuk/The New York Times Vice President Joseph R. Biden Jr. on Thursday administered the oath of office to Cory A. Booker, recently elected to the Senate. Mr. Booker's arrival in Washington did not come with the same political portent rendered by another high-profile senator who arrived here via a special election - Scott Brown, Republican of Massachusetts, whose 2010 victory signaled the ensuing power of the Tea Party movement, cost Democrats a 60-vote supermajority and placed a Republican in the seat held for nearly half a century by Edward M. Kennedy. Senator Brown lost the seat to Elizabeth Warren in 2012, thus ending his swing-vote-laden tenure. But Senator Booker was met with a fair amount of attention from his fellow Democrats, whose excitement seemed to stem less from the fact that, after Senator Frank R. Lautenberg died in June, their party retained the seat as expected - but rather at his significant national star wattage and the fund-raising potential it may bring. He joins Senator Tim Scott of South Carolina, who was appointed by Gov. Nikki Haley earlier this year to replace Jim DeMint, who retired, as one of only two black senators. Mr. Booker began his day, he said, with his mother, Carolyn Booker, in the office of Representative John Lewis, Democrat of Georgia, the civil rights leader. "It was really emotional and moving," he said. Mr. Booker, whose bright purple tie marked him already as a semi-exciting fashion force in the upper chamber, then repaired to a photo opportunity before three American flags with the Senate majority leader, Harry Reid of Nevada, and Ms. Booker. The three entered the camera-packed tiny ceremonial office off the Senate chamber through a door flanked by oil-paint portraits of Presidents John F. Kennedy and Franklin D. Roosevelt. Mr. Reid declined to take questions, and his newest acolyte kept silent. Just before noon, Mr. Booker greeted his new colleagues. Mr. Scott was the first Republican to come into the chamber, and sat smiling at his desk before greeting Mr. Booker. Vice President Joseph R. Biden Jr. then administered the brief oath before welcoming him, as those gathered applauded. It will be up to Mr. Booker to determine the sort of public swath he wishes to cut in Congress. Will he seek to emulate other politicians - like Hillary Rodham Clinton, Al Franken and Ms. Warren - who entered the Senate already famous and generally kept low profiles and avoided the news media, focusing instead on legislation? Or perhaps Mr. Booker will take his cues from newcomers like the Republicans Ted Cruz of Texas and Rand Paul of Kentucky, who though not as well known when they entered the Senate have used their new platforms to establish themselves in short order as national figures, drawing criticism from colleagues for ignoring Senate protocol. Mr. Booker said he had been advised to "be humble, learn as much as you can," and, further, "don't let the Senate change you - try to change the Senate." Colleagues from both sides of the aisle pledged to work with him, he said, moments before Republicans filibustered two nominees appointed by President Obama. After he was sworn in, the Senate moved on to other business. Mr. Booker stood in the well for the first roll call vote of his Senate career - a procedural motion on one of the troubled nominations - and appeared astonished and mildly afraid when his name was called. He then went to the Old Senate Chamber for a ceremonial swearing in, and jokingly asked Mr. Biden for a room at the Naval Observatory while he looks for a place to live. Mr. Booker visited with Mr. Obama at the White House on Thursday afternoon, a rare treat for a freshman senator.