With Mr. McCarthy elected, he immediately turned to swearing in the 434 members of the House to officially seat the 118th Congress. Republicans announced that they would wait until Monday to consider a package of rules for the chamber, which is expected to enshrine many of the compromises Mr. McCarthy made to win his post.
The concessions Mr. McCarthy agreed to, which he detailed in a party conference call early Friday, would diminish the speaker’s power considerably and make for an unwieldy environment in the House, where the slim Republican margin of control and the right-wing faction’s appetite for disarray had already promised to make it difficult to control.
“What we’re seeing is the incredibly shrinking speakership, and that’s most unfortunate for Congress,” former Speaker Nancy Pelosi, Democrat of California, said as she entered the chamber on Friday afternoon.
Mr. McCarthy agreed to allow a single lawmaker to force a snap vote at any time to oust the speaker, a rule that he had previously refused to accept, regarding it as tantamount to signing the death warrant for his speakership in advance.
Also part of the proposal, Republicans familiar with it said, was a commitment by the leader to give the ultraconservative faction approval over a third of the seats on the powerful Rules Committee, which controls what legislation reaches the floor and how it is debated. He also agreed to open government spending bills to a freewheeling debate in which any lawmaker could force votes on proposed changes.
Those compromises delivered a breakthrough for Mr. McCarthy, who in votes on Friday afternoon won support from a sizable chunk of the Republicans who had consistently refused to back him — though he remained short of the majority to win.
They included Representatives Dan Bishop of North Carolina, Josh Brecheen of Oklahoma, Michael Cloud of Texas, Andrew Clyde of Georgia, Byron Donalds and Anna Paulina Luna of Florida, Paul Gosar of Arizona, Andy Harris of Maryland, Mary Miller of Illinois, Ralph Norman of South Carolina, Andy Ogles of Tennessee, Scott Perry of Pennsylvania, and Chip Roy and Keith Self of Texas. Representative Victoria Spartz of Indiana, who had voted “present” in previous ballots, also voted for Mr. McCarthy in the 12th vote.
