Mike Johnson was elected Speaker of the House, Embracing a Hard-Right Conservative.

Republicans chose a little-known Louisiana lawmaker to break the deadlock in the House.

On Wednesday, they elected Representative Mike Johnson from Louisiana as the 56th speaker of the House of Representatives. Republicans chose an unknown hard-liner to end their infighting after three weeks.

Mr. Johnson, a 51-year-old architect of the effort to overturn the 2020 election, reinforced the Republican Party’s right-leaning stance. It came after a historic fight when the hard right ousted Speaker Kevin McCarthy on October 3. It raged on as the divided House G.O.P. nominated and swiftly discarded three other candidates to succeed him.

After much arguing and threats, the right-wing and mainstream Republicans came together to elect Mr. Johnson, 51, in a 220-to-209 vote.

The vote put him second in line for the presidency, capping an extraordinary period of twists and turns on Capitol Hill. It marked a victory for the far right, which has become a dominant force in the Republican Party. It rose to October 3 to dictate the removal of an establishment speaker and the installation of an arch-conservative replacement.

Republicans stood up and clapped when Mr. McHenry declared Mr. Johnson the elected speaker.

In a speech that traced his ascent up the political ladder in Louisiana to Congress, Mr. Johnson pledged to try to “restore the people’s faith in this House.” He cited sending aid to Israel, fixing a “broken” southern border, and reining federal spending as his top legislative priorities.

“The challenge before us is great, but the time for action is now,” Mr. Johnson said shortly after being elected. “And I will not let you down.”

In his speech on the House floor, Mr. Johnson constantly referred to scripture, evoking his evangelical Christian faith.

“It is obvious from the Bible that God is the one who raises those in authority,” he said. “He raised each of you, all of us. And I believe God has ordained and allowed each of us to be brought here for this specific moment.”

In a nod to the simmering frustrations among the hard-right flank of the party that ultimately deposed Mr. McCarthy, the California Republican, Mr. Johnson pledged that his office “is going to be known for decentralizing power.”

Elected to Congress in 2016, Mr. Johnson is the youngest lawmaker in decades to become speaker.

He may also be the most conservative. Mr. Johnson, a lawyer, is the former chairman of the Republican Study Committee and sponsored legislation that would effectively bar the discussion of sexual orientation or gender identity at any institution serving children younger than ten that receives federal funds. He supports a national abortion ban and has co-sponsored a 20-week abortion ban.

Mr. Johnson was on Trump’s impeachment defense team and helped recruit House Republicans to support a lawsuit against the 2020 election results. He was also an architect of Mr. Trump’s bid to object to certifying them in Congress on January 6, 2021. Mr. Trump praised him on Wednesday after his election, calling the Louisiana Republican “a fantastic gentleman.”

“He’s going to do a great job,” Mr. Trump said.

Democrats were scathing in assessing Mr. Johnson’s ascent to the speakership. Pete Aguilar, the Democratic conference chairman from California, said the speaker fight became a competition to please Donald Trump.

They heckled mainstream Republicans facing tough re-election contests next year in the January 6 districts as they rose to vote for Mr. Johnson. After Representatives Mike Lawler and Marc Molinaro, both of New York, each voted for the Louisiana Republican, a Democrat could be heard yelling, “Bye-bye!”

Mr. Johnson immediately faced many challenges that dogged his predecessor, Mr. McCarthy. He is confronting a mid-November deadline to pass a measure to fund the government to avert a shutdown. And he will need to lead a conference deeply divided over foreign policy as Congress considers the Biden administration’s $105 billion funding request for Israel, Ukraine, and the southern border.

Mr. Johnson’s opposition to funding the war in Ukraine has become a contentious issue within the G.O.P.

After President Biden was told during a White House news conference that a new speaker had been elected, Mr. Biden said, “I hope that’s true. Because we have to get moving.”

Asked whether he was concerned, given the Republican speaker’s history, that he would try again to overturn the election in 2024, Mr. Biden answered flatly: “No. I was not worried the last campaign would overturn the election.”

In a statement later on Wednesday, Mr. Biden said: “We need to move swiftly to address our national security needs and to avoid a shutdown in 22 days. Even though we have real disagreements about important issues, there should be a mutual effort to find common ground wherever possible.”

In the end, Mr. Johnson brought together the party’s hard-right and mainstream flanks that had taken turns sinking speaker candidates. House Republicans joined forces to address constituents’ distress and end dysfunction.

Representative Tom Emmer of Minnesota, the No. 3 Republican, stated that, from an outside point of view, these last few weeks undoubtedly look like chaos, confusion, and no end in sight. His party’s hard-right flank dumped him within hours of being nominated for speaker on Tuesday. “But from my perspective, this is one of the greatest experiences in the recent history of our republic.”

Mainstream conservatives who backed Mr. Johnson hoped to move to pull the House out of its funk quickly. Almost immediately after Mr. Johnson was elected, lawmakers debated a resolution expressing solidarity with Israel and condemning Hamas, which passed overwhelmingly. Image

“Despite our differences, let’s work together for the country’s benefit,” Mr. Lawler wrote on social media with a photo of him and Mr. Johnson shaking hands.

Republicans rejected Jim Jordan as a speaker because he supported Trump’s efforts. But some said they did not have the same concerns about Mr. Johnson.

Despite his significant involvement in Johnson’s, Ken Buck denied Mr. Johnson’s role in the post-election efforts. “People” can make mistakes and still be excellent speakers,” Mr. “uck said.

Those hard-right Republicans who ousted Mr. McCarthy considered Mr. Johnson a valid reason for their decision.

“This “affirms our path,” representative Bob Good of Virginia said.