The 220 to 209 party-line vote elevated Johnson to a speaker's chair that has been vacant since Kevin McCarthy was ousted on Oct. 3 by a small group of hardline Republicans angry about a deal with Democrats that averted a partial government shutdown.
In the weeks that followed, Republicans who narrowly control the House considered and rejected three possible replacements before settling on Johnson, 51, a Louisiana lawyer backed by former President Donald Trump who spent years advancing conservative policies like school prayer.
"We will restore trust in this body. We will advance a comprehensive conservative policy agenda, combat the harmful policies of the Biden Administration, and support our allies abroad," Johnson said in a statement shortly after the vote.
First elected in 2016, Johnson will be the least experienced House speaker in decades. He is best known as the author of an unsuccessful appeal by 126 House Republicans to get the Supreme Court to overturn election results in states that Trump had lost in the 2020 presidential election.
Johnson declined to answer a question about that effort shortly after his nomination on Tuesday night, while other Republicans booed and heckled the reporter who asked it.
In a letter to colleagues, Johnson has vowed to advance overdue spending legislation and ensure that the U.S. government does not shut down when current funding expires on Nov. 17.
He will also have to respond to Democratic President Joe Biden's $106 billion spending request for aid to Israel, Ukraine and U.S. border security. While his Republicans broadly support funding for Israel and the U.S. border, they are divided over further support for Ukraine.
The uncertainty has also helped to push up the U.S. government's borrowing costs. The government posted a record $1.7 trillion deficit for the most recent fiscal year, in part due to higher interest payments.
Democrats blasted his efforts to overturn the 2020 election, as well as his conservative stances on abortion and gay marriage. But some said they were at least happy the House finally would be able to get back to work.
"Our country cannot be governed without a Speaker of the House, so I am relieved that Republicans have finally elected a new leader. However, I am deeply concerned by Congressman Mike Johnson’s record of election denial and attacks on reproductive rights," Democratic Representative Jim Himes said.
While House leaders typically focus on fundraising and vote counting, Johnson is better known as an advocate for conservative social positions.
He has supported legislation that bars gender-related surgery and hormone treatment for transgender teens, prohibits mask mandates on airplanes, and tightens immigration and abortion restrictions.
Republicans narrowly control the House by a 221-212 margin, leaving them with little room for error on controversial votes. Their divisions were on display over the past few weeks, as they nominated three candidates for speaker — Steve Scalise, Jim Jordan and Tom Emmer — but were unable to provide the 217 votes needed to win the speaker's gavel.
As speaker, Johnson will have to confront the same challenges that felled McCarthy and stymied his would-be successors. They include the demands of the caucus' hardline members and the reality that with a Democratic majority in the Senate and Biden occupying the Oval Office, no laws can currently be passed in Washington without bipartisan support.