Rep. Patrick McHenry, R-N.C., nominated McCarthy for speaker, prompting sustained applause from the Republican caucus.

"I want to start by thanking the men and women who make this House run," McHenry said. "From the janitorial staff, to the parliamentarians, to the doorkeepers, to the sergeant at arms, to the Capitol Police officers, to the men and women who make this institution run, thank you."

The remarks received a standing ovation from both sides of the aisle.

McHenry went on to address the party's struggles in swiftly electing a speaker, stating, "We know it's messy but open and transparent debate sets us apart from authoritarian regimes."

House Clerk Cheryl Johnson gaveled in the chamber just after 10 p.m.

Members were starting a 14th vote for a speaker. Republican leader McCarthy said he's confident he will have the support tonight to clinch the speaker's gavel.

Fifteen Republican holdouts flipped for McCarthy this afternoon after days of stalemate in the speakership battle. He will need more of his opponents to switch their stances or vote "present" tonight in order to win.

Former President Donald Trump spent the day calling the Republican holdouts, including the remaining six defectors, in hopes of getting them to flip their votes to McCarthy, sources familiar with the calls told ABC News. But Trump's endorsement of McCarthy earlier this week was essentially a non-factor.

House Republican Leader Kevin McCarthy seems all but certain that he has the votes to push this over the finish line tonight.

"I'll have the votes," McCarthy said as he headed off the House floor after the chamber adjourned until 10 p.m.

"We'll come back tonight, and I believe at that time we'll have the votes and finish this once and for all," he said.

McCarthy attempted to portray the drawn-out negotiations and multiple ballots -- the most since before the Civil War -- as a positive thing. "This is the great part," he said. "Because it took so long now we learned how to govern."

But to be clear, this is still a bit of a numbers game and McCarthy doesn't have the votes yet.

He still needs to flip votes. If there are zero absences , McCarthy would need to flip two of the six remaining holdouts: Reps.-elect Andy Biggs, Lauren Boebert, Eli Crane, Matt Gaetz, Bob Good and Matt Rosendale.

But there are other paths to the speakership, again assuming no absences when members reconvene: Either one flips of remaining holdouts; one flip and one (or more) "present" votes; if no flips, three or more "present: votes.

Asked by ABC News what he says to those who think he's giving up too much to a small percentage of his conference, McCarthy argued that it was actually the whole conference that came together on these reforms.

"The whole conference worked on these reforms. These reforms are actually very good. It empowers the members," he said.

--ABC News Katherine Faulders, Lauren Peller, Will Steakin and Ben Siegel

Rep. Andy Harris of Maryland appears to be the only remaining holdout Republican to flip his vote for McCarthy so far in the 13th round of voting, signaling more momentum for McCarthy but not enough to win the speakership.

While no other Republican was formally nominated this round, five voted for Rep. Jim Jordan, R-Ohio.

Reps. Andy Biggs, R-Ariz., Lauren Boebert, R-Colo., Matt Gaetz, R-Fla., Bob Good, R-Va., Rep. Matt Rosendale, R-Mont., and Rep.-elect Eli Crane remain in the "Never Kevin" crowd.