WASHINGTON -- Miami Republican Marco Rubio, who harnessed tea party fervor to topple a one-time popular governor and emerge as a conservative star, became Florida's newest senator Wednesday. He pledged to uphold his campaign promises -- to slice the federal $14 trillion debt and repeal President Barack Obama's landmark healthcare law. "My expectations are very straightforward," Rubio told reporters just before his swearing-in. "I ran because I told people I want to be the U.S. senator from Florida because I believe this country is headed in the wrong direction. I think both parties are to blame. I want to go to Washington, D.C., stand up to the direction it is taking our country and offer a clear alternative. That's what I ran on; that's what I'm going to be for the next six years." Like other newcomers to Washington, Rubio joins a deeply divided Congress following last November's elections. Republicans now control the House, while Democrats remain the majority in the Senate. The 39-year-old sought to brush aside the buzz that has accompanied his ascension, calling talk of being a vice presidential or even presidential candidate in 2012 part of the media "circus'' inside Washington. "They'll talk about somebody else next week," Rubio said. "I'm here to be the United States senator from Florida and the best senator I can. That's what I ran for; that's what I want to be." Rubio's swearing-in was rich with senatorial tradition: Florida's senior senator Democrat Bill Nelson, accompanied Rubio as he walked down the center aisle of the Senate to take the oath of office. Also with Rubio was former Florida Sen. Mel Martinez, a fellow Cuban-American Republican whom Rubio succeeds, after former Sen. George LeMieux temporarily filled the seat. Rubio, serious in a dark suit and red, polka-dotted tie, briefly looked up as Vice President Joe Biden -- sitting as Senate president -- administered the oath at 12:28 p.m. Carrying a Bible, Rubio flashed a big smile and took his seat on the back row of the Republican side of the aisle. "It's humbling," Rubio told reporters. "I don't feel I won anything other than the opportunity to serve." The former Florida House speaker took office along with seven new Florida Republican members of the House, including Rep. David Rivera of Miami, who is under a cloud of controversy back in South Florida. Since his victory in the Nov. 2 election over Democrat Joe Garcia, Rivera has become the target of a criminal investigation by Miami-Dade prosecutors and police, which is focused on his personal and campaign finances while serving as a state representative. Also taking office, tea party favorite Rep. Allen West, who became the first Republican since the 1990s to join the heavily Democratic Congressional Black Caucus. He took his seat at the caucus event Tuesday1/4 next to Miami Democrat Rep. Frederica Wilson, who replaced former Rep. Kendrick Meek. "I am humbled and honored to be a part of this historic body of Congress," said West, joined by his wife, Angela, and two teenage daughters, Aubrey and Austen. "I have been given the trust of the constituents of the 22nd district of Florida. I will not let them down." West took the oath accompanied by former Rep. Clay Shaw, who had represented West's Broward/Palm Beach district before former Rep. Ron Klein, a Democrat, ousted Shaw in 2006. Wilson, accompanied by five grandchildren, took the oath with new House Speaker John Boehner, R-Ohio, wearing a red-sequined cowboy hat. Florida's new delegation has more clout than ever, with several lawmakers holding committee chairmanships in the House. "I was like a little kid, I couldn't sleep," said longtime Rep. John Mica, of Orlando, who will chair the House Transportation and Infrastructure Committee. "It's a remarkable day for Florida." At a packed reception Tuesday night at Florida House, the state's Capitol Hill embassy, Rubio basked in the adulation of a giddy crowd. He drew laughter when he told Nelson he looked forward to "walking down the aisle with you'' and cautioned the crowd that "after all the pomp and circumstance is over we have a lot of hard work ahead of us." Asked by a reporter where he'll fit into the GOP political spectrum -- favoring bipartisanship or opposing every Democratic bill -- Rubio said Republicans should "only oppose their bad ideas, and they have a lot. "This election cycle, the people from across the country and Florida elected people who came up here on on a very clear mandate," Rubio said. "That mandate is get control of the spending problem, figure out ways for the federal government to help economic growth, not hinder it and make sure America continues to be the strongest military power in the world." In the House Wednesday, newly elected speaker Boehner hailed the Republican Party's return to control of the body, vowing a more open legislative process but acknowledging that "a great deal of scar tissue has built up on both sides of the aisle." GOP lawmakers, who picked up 64 House seats in the November elections, cheered loudly when Boehner defeated Democrat Nancy Pelosi in the roll call for speaker. The veteran Ohio lawmaker's rise to the speakership was guaranteed by his party's midterm triumphs, which ended Pelosi's four-year reign. Nineteen House Democrats refused to vote for Pelosi as speaker, baring the lingering wounds from last fall's bitter elections. Countless GOP campaign ads had depicted Pelosi and her allies as out-of-touch liberals. Eleven House Democrats kept campaign promises Wednesday by voting for fellow centrist Heath Shuler, D-N.C.