The 113th Congress convened at 12 noon EST, the constitutionally mandated time, with pomp, pageantry and politics on both sides of the Capitol.
Boehner, bruised after weeks with his fractious caucus and negotiations with the White House on the fiscal cliff, won a second, two-year term as leader with 220 votes. Despite grumbling in the GOP ranks, just 10 Republicans voted for someone other than Boehner.
Democratic leader Nancy Pelosi got 192 votes.
In a chamber packed with members and their children, Pelosi delivered a generous introduction to her rival and handed the gavel to Boehner, who struggled to hold back tears.
Boehner alluded to the continuing fight over government spending that was far from settled by the tax deal with President Barack Obama. Fierce battles loom in the coming weeks over automatic spending cuts and increasing the nation's borrowing authority.
"The American Dream is in peril so long as its namesake is weighed down by this anchor of debt. Break its hold, and we begin to set our economy free. Jobs will come home. Confidence will come back," Boehner said.
Addressing the 80-plus new members, Boehner told them that if they came "to see your name in lights or to pass off political victory as accomplishment, you have come to the wrong place. The door is behind you."
"If you have come here humbled by the opportunity to serve; if you have come here to be the determined voice of the people; if you have come here to carry the standard of leadership demanded not just by our constituents but by the times, then you have come to the right place," he said.
Rep. John Dingell, D-Mich., the longest serving member, administered the oath to Boehner, who then swore in the members.
In the Senate, Vice President Joe Biden swore in 12 new members elected in November, lawmakers who won another term and South Carolina Republican Tim Scott. The former House member was tapped by Gov. Nikki Haley to fill the remaining term of Sen. Jim DeMint, who resigned to head a Washington think tank.
Applause from members and the gallery marked every oath-taking. Looking on was former Vice President Walter Mondale.
Shortly before the session, Sen. Mark Kirk, R-Ill., who had been absent for the past year while recovering from a stroke, slowly walked up the 45 steps to the Senate, with Biden nearby and the Senate leaders at the top of the stairs to greet him.
"A courageous man," said Senate Majority Leader Harry Reid, D-Nev. Members of the Illinois congressional delegation and senators stood on the steps.
As he entered the building, resting on a cane, Biden and Sen. Joe Manchin, D-W.Va., helped Kirk take off his coat. The senator said he was glad to be back.
While the dozens of eager freshmen are determined to change Washington, they face the harsh reality of another stretch of divided government. The traditions come against the backdrop of a mean season that closed out an angry election year.
A deal to avert the "fiscal cliff" of big tax increases and spending cuts split the parties in New Year's Day votes, and the House's failure to vote on a Superstorm Sandy aid package before adjournment prompted GOP recriminations against the leadership.
"There's a lot of hangover obviously from the last few weeks of this session into the new one, which always makes a fresh start a lot harder," Rep. Kevin Brady, R-Texas, said.
For all the change of the next Congress, the new bosses are the same as the old bosses.
Obama secured a second term in the November elections, and Democrats tightened their grip on the Senate for a 55-45 edge in the new two-year Congress, ensuring that Reid will remain in charge. Republicans maintained their majority in the House but will have a smaller advantage, 233-200. Former Democratic Rep. Jesse Jackson Jr.'s Illinois seat and the one held by Scott are the two vacancies.
On the eve of the vote, Boehner mollified angry Republicans from New York and New Jersey on Wednesday with the promise of a vote Friday on $9 billion of the storm relief package and another vote on the remaining $51 billion on Jan. 15.
The GOP members quickly abandoned their chatter about voting against the speaker.
The new Congress still faces the ideological disputes that plagued the dysfunctional 112th Congress, one of the least productive in more than 60 years. Tea party members within the Republican ranks insist on fiscal discipline in the face of growing deficits and have pressed for deep cuts in spending as part of a reduced role for the federal government. Democrats envision a government with enough resources to help the less fortunate and press for the wealthiest to pay more in taxes.
"We can only hope for more help," said Manchin, who was re-elected in November. "Any time you have new members arriving you have that expectation of bringing fresh ideas and kind of a vitality that is needed. We hope that they're coming eager to work hard and make some difficult decisions and put the country first and not be bogged down ideologically."
The next two months will be crucial, with tough economic issues looming. Congress put off for just eight weeks automatic spending cuts to defense and domestic programs that were due to begin with the new year. The question of raising the nation's borrowing authority also must be decided. Another round of ugly negotiations between Obama and Congress is not far off.
There are 12 newly elected senators - eight Democrats, three Republicans and one independent, former Maine Gov. Angus King, who will caucus with the Democrats. They will be joined by Scott, the first black Republican in decades.
In a sign of some diversity for the venerable body, the Senate will have three Hispanics - Democratic Sen. Bob Menendez of New Jersey, Republican Sen. Marco Rubio of Florida and one of the new members, Republican Ted Cruz of Texas. There will be 20 women in the 100-member chamber, the highest number yet.
At least one longtime Democrat, Sen. John Kerry of Massachusetts, will be departing in a few weeks, nominated by Obama to be secretary of state. That opens the door to former Republican Sen. Scott Brown, the only incumbent senator to lose in November's elections, to possibly make a bid to return to Washington.
Eighty-two freshmen join the House - 47 Democrats and 35 Republicans. Women will total 81 in the 435-member body - 62 Democrats and 19 Republicans.
In the Senate, Reid and Republican leader Mitch McConnell are negotiating possible changes in the rules as lawmakers face a bitter partisan fight over filibusters, according to a Senate Democratic leadership aide who spoke on condition of anonymity because he was not authorized to speak publicly about private matters.
Reid has complained that Republicans filibuster too often and has threatened to impose strict limits with a simple majority vote. That step could set off retaliatory delays and other maneuvers by Republicans, who argue that they filibuster because Reid often blocks them from offering amendments.
The aide said Reid was preserving the option of making changes with a simple majority vote.