In a slow-moving roll call that mixed politics with pageantry, 236 Republicans called out the Wisconsin Republican's name as their pick for the top job. That put Ryan atop a chamber that has been awash in tumult ever since defiant conservatives hounded Rep. John Boehner, R-Ohio, into announcing his resignation from that post last month.
Just nine hardline conservatives lined up against Ryan, instead backing the little-known Rep. Daniel Webster, R-Fla. But most, including members of the rebellious House Freedom Caucus, backed Ryan — though it was clear that future tensions between them and Ryan could not be discounted.
Watching the vote from the visitors' gallery was Mitt Romney, the GOP's unsuccessful 2012 presidential nominee who vaulted Ryan, 45, to national prominence by selecting him as his vice presidential running mate. Also in the audience were Ryan's wife Janna and their three young children, who gained some attention after Ryan insisted he would take the time-draining speaker's post only if he could carve out time with his family.
Before the vote, now former Speaker Boehner bade farewell to his colleagues after a quarter-century House career, including the last five as speaker.
"I leave with no regrets, no burdens," said Boehner in a 10-minute speech. "If anything, I leave the way I started, just a regular guy, humbled by the chance to do a big job."
Boehner's valedictory did not lack his trademark tears, and he earned a bipartisan standing ovation before even starting when he pulled out a box of tissues.
Ryan's ascension comes as Congress neared completion of a bipartisan accord to avert a jarring federal default next week and likely prevent a December government shutdown by setting spending levels for the next two years.
The House approved the bill Wednesday 266-167, with final Senate passage on track in a few days, despite opposition from conservatives including senators seeking the GOP presidential nomination.
The budget vote underscored Ryan's challenge in leading Republicans who often have scant interest in compromise, especially with a GOP presidential contest dominated by candidates who vilify Washington insiders. Republicans opposed the budget deal by 167-79, but Democrats supported it unanimously.
Conservatives complain that Boehner had been excessively powerful, forcing bills to the House floor without rank-and-filed input, dictating committee chairs and punishing rebels. One Freedom Caucus leader, Rep. Raul Labrador, R-Idaho, said conservatives expect Ryan to alter that.
"We're going to have his back for the next few months and make sure that we give him the opportunity to show that he can be the leader that we hope he can be," Labrador said.
Boehner's resignation prompted a month of GOP turbulence after the Freedom Caucus derailed the candidacy of the heir-apparent, Majority Leader Kevin McCarthy, R-Calif. Establishment Republicans pressured a reluctant Ryan to seek the speakership, viewing him as their best shot at patching the GOP's ragged ruptures.
Ryan has been in Congress 17 years and has strong ties with all wings of the GOP. Past chairman of the House Budget Committee and current head of the Ways and Means Committee, he has put his imprint on deficit reduction, tax, health and trade legislation — prime subjects that have raised his stature and put him at the center of many of Congress' highest profile debates.
Ryan will be the youngest speaker since Rep. James Blaine, R-Maine, who was 39 when he took the job in 1869.
Al Jazeera and The Associated Press