WASHINGTON — Representative Kevin McCarthy of California, the House Republican leader, took to the House floor at 8:38 p.m., determined to make history, even if he had no hope of derailing the Democrats’ roughly $2 trillion bill to strengthen the social safety net and combat climate change.

Eight hours and 32 minutes later, he stopped talking, with a few groggy Republicans remaining to applaud his performance. The stunt did nothing to break Democrats’ resolve to pass the legislation, but it did set a record for the longest continuous House speech in modern history, surpassing one that Speaker Nancy Pelosi set in 2018, when she was serving in Mr. McCarthy’s current post of minority leader. For Mr. McCarthy, it may also have bolstered his campaign to take over Ms. Pelosi’s job, becoming the next speaker if Republicans seize control in next year’s midterm elections.

“Personally, I didn’t think I could go this long,” Mr. McCarthy said toward the end of his exhausting, meandering and at times nonsensical monologue as some of the people behind him struggled to keep their eyes open. Finally, after 5 a.m., he finished. “With that, Madam Speaker, I yield back,” he said.

Ms. Pelosi had left hours before.

Mr. McCarthy, the top Republican in the House, did stave off a planned Thursday vote as he railed against President Biden and his agenda. But the Californian had another goal: Secure the respect — and possibly the support — of his party’s restive conservatives, who have been told repeatedly by their leader, Donald J. Trump, that other Republican leaders have not fought Democrats hard enough. Hours after concluding his speech, Republicans fist-bumped him and clapped him on the back as he arrived on the House floor for votes.

“You galvanize people, right? You catch people’s attention, and you demonstrate to them that we’re resolved to fight,” said Representative Chip Roy, a Texas Republican who is known for forcing procedural delays. He added, “Look, I want the leader to fight, and that was good. Go fight. Let’s fight more. Let’s throw everything we’ve got at this nonsense.”

Democrats said all he accomplished was ensuring that House passage of one of the most consequential domestic policy bills in a half century would happen in broad daylight.

“I thought McCarthy was addressing issues he has in his own caucus,” Representative Richard E. Neal of Massachusetts, the chairman of the Ways and Means Committee, said. He argued that the “far-reaching, successful implications” of the legislation would far outweigh the speech.

The debate over the bill had been scheduled to last 20 minutes before Mr. McCarthy — who is not known for his soaring oratory — took over to deliver a circuitous, rambling speech stuffed with Republican talking points against the legislation and punctuated with riffs about history. He skittered through President Ronald Reagan’s missile defense initiative, his personal friendship with Tesla’s founder, Elon Musk, and, at one point, a lengthy disquisition on the famous painting of George Washington crossing the Delaware River on his way to the Battle of Trenton.

China came up a lot and repeatedly: its responsibility for the coronavirus, its hypersonic missile, and its mock-ups of American battleships. In one aside, he suggested that not even the Chinese would fortify the Internal Revenue Service to force its citizens to pay their taxes the way Democrats had in their bill.

As the clock ticked toward midnight and then long after, Mr. McCarthy sometimes seemed to lose the thread, spouting what sounded like a Mad Libs of Republican attacks.

“Inflation is at a 31-percent high, gas prices, Thanksgiving, a border that in a few months breaks every record of the last three years combined,” he shouted at one point.

The whole speech felt like a circular loop, touching on the same issues over and over. When Ms. Pelosi gave up on a vote and dismissed Democrats after midnight, he said his opponents might be leaving, but he would not.

“I know some of you are mad at me, think I spoke too long,” he said. “But I’ve had enough. America has had enough.”

Representative Madison Cawthorn, a hard-line Republican from North Carolina, sat behind him, stuffing his lip with chewing tobacco and spitting in a cup. Mr. McCarthy, for his part, sustained himself with peppermint candies, unwrapped one by one by aides.

While the House has no equivalent to the Senate filibuster, Mr. McCarthy used the so-called “magic minute” a House custom that allows leaders to talk for as long as they want when they are recognized for their one minute of floor time. Ms. Pelosi used the tactic when she was minority leader in 2018 to speak for just over eight hours about the young undocumented immigrants known as Dreamers.

The speech by Ms. Pelosi was thought at the time to have set the record for the longest continuous speech in the chamber, dating to at least 1909.

“It is a feat of epic proportions to speak for four hours straight and not produce a single memorable phrase, original insight or even a joke,” Representative Jamie Raskin, Democrat of Maryland, wrote on Twitter. “McCarthy thinks he is a wit but so far he has proved he is only half right.”

Representative Alexandria Ocasio-Cortez, Democrat of New York, who attempted to interject twice during Mr. McCarthy’s speech, said the Republican leader had been “auditioning for his base.”

“I think he wanted to say he did it longer than Nancy Pelosi,” Ms. Ocasio-Cortez said on Friday. “But if he wanted to outdo her, he should’ve done it in stilettos.”

Emily Cochrane contributed reporting.