Gov. Ron DeSantis of Florida has replaced his campaign manager, Generra Peck, in the latest shake-up in his weekslong attempt to reinvigorate his struggling bid for the White House.

Replacing Ms. Peck as campaign manager is James Uthmeier, the governor’s chief of staff and one of his most trusted advisers but someone with little campaign experience. In another significant shift, David Polyansky, one of the architects of the early-state strategy at Never Back Down, the main pro-DeSantis super PAC, is moving from that outside group to the campaign. The Messenger earlier reported the moves.

The campaign staffing changes — the third round in less than a month — come as Mr. DeSantis and his message have so far struggled to connect with Republican primary voters. Mr. DeSantis has built his candidacy on being a more electable Republican and the type of politician who can actually accomplish what he promises.

But a recent New York Times/Siena College poll showed that Republican voters viewed former President Donald J. Trump as a stronger candidate against President Biden, and as the Republican contender more likely to “get things done.”

Ms. Peck, who will stay on as the campaign’s chief strategist, had drawn intense criticism from some of Mr. DeSantis’s allies and donors after heavy spending led to a fund-raising shortfall.

In response, the campaign had to lay off more than a third of its staff and start holding smaller events — a leaner operation more suited to a candidate who is trailing well behind Mr. Trump. The successive rounds of changes have been an enduring distraction for Mr. DeSantis’s campaign.

In 2022, Ms. Peck, 36, oversaw Mr. DeSantis’s overwhelming re-election as governor, making herself an invaluable confidante to the governor and his wife, Casey. But she had never worked on a presidential campaign, much less run one. Mr. Uthmeier, 35, appears to have even less direct political experience than Ms. Peck, underscoring the degree to which Mr. DeSantis values personal loyalty and how the DeSantises’ trust often matters most.

Mr. Uthmeier, a member of the Federalist Society, the conservative legal group, served as general counsel to the governor and also worked in the Trump administration. He began his career as a litigation associate in the Washington office of the firm Jones Day, according to the Federalist Society’s website.

“James Uthmeier has been one of Gov. DeSantis’s top advisers for years, and he is needed where it matters most: working hand in hand with Generra Peck and the rest of the team to put the governor in the best possible position to win this primary and defeat Joe Biden,” Andrew Romeo, the campaign’s communications director, said in a statement.

Mr. Uthmeier said in a statement that “people have written Governor DeSantis’s obituary many times” but that his boss “has proven that he knows how to win.”

The arrival of Mr. Polyansky, who has worked closely for years with the super PAC’s main strategist, Jeff Roe, is seen as a significant change, as well. The super PAC and the campaign have had some tensions over strategy.

Mr. Polyansky has a precise understanding of politics in Iowa, where Mr. DeSantis’s fortunes increasingly ride on a strong showing. But Mr. Polyansky will also bring Mr. Roe’s thoughts about the campaign and its messaging directly into its top levels.

Under the current byzantine rules of campaign finance, strategists with the super PAC can directly join the campaign, but the reverse is prohibited.

Mr. Polyansky, who had been overseeing the super PAC’s early state operations, was on the trail in recent weeks with Mr. DeSantis as the group put together a bus tour for the governor. After the campaign’s cash crunch, the super PAC began taking over many of the functions normally associated with a campaign, like organizing retail stops and speaking events.

“David Polyansky will also be a critical addition to the team, given his presidential campaign experience in Iowa and work at Never Back Down,” Mr. Romeo said.

By the time Mr. DeSantis replaced her, Ms. Peck, who has limited strategic experience, was widely seen as miscast in the campaign manager role, even by those who liked her. She had come under fire for building a campaign team so quickly that Mr. DeSantis was forced to lay off roughly 40 percent of his aides only two months into his candidacy.

Ms. Peck allowed aides running a “DeSantis War Room” Twitter account to post online videos freely but outside normal approval channels, according to a person familiar with the campaign’s operations. The account shared a video that the campaign had secretly made and pushed out to a friendly supporter to post first, making it appear organic. The video was widely criticized as homophobic.

Ms. Peck also wrote a memo without the input or knowledge of some senior campaign staff members that appeared to give direction to the super PAC, and was indirectly critical of some of its actions, like going off the television airwaves in New Hampshire.

During a campaign retreat with donors in Park City, Utah, about two weeks ago, a few people raised concerns with Mr. DeSantis and his wife about the state of his campaign’s finances, according to three people briefed on the discussions.

The campaign’s finances were so worrying that Mr. Uthmeier, while still chief of staff, received a personal briefing on its finances from Ethan Eilon, now the deputy campaign manager, and then delivered an assessment to the governor.

Mr. Uthmeier joined the governor’s office shortly after Mr. DeSantis took power in 2019. Since Mr. DeSantis announced his run for president, Mr. Uthmeier has sometimes worn two hats: In recent weeks, he also spent time raising money for the campaign. Mr. DeSantis has defended his aide’s actions, saying he was doing so as a volunteer.

Nikki Fried, the chairwoman of the Florida Democratic Party, filed ethics and election complaints against Mr. Uthmeier and two other top aides to Mr. DeSantis. She said the officials had illegally solicited contributions from lobbyists and endorsements from state lawmakers, who said they felt pressured into agreeing because Mr. DeSantis had yet to sign the state budget.

Perhaps reflecting the uncertain nature of presidential politics, Mr. Uthmeier is not permanently giving up his seat in the governor’s office. Instead, he is taking a “leave of absence” as chief of staff, according to a spokesman for the governor. Another influential DeSantis aide, Alex Kelly, will serve as acting chief of staff.

Mr. Trump’s allies took the news as yet another opportunity to gloat about his lead in the polls and Mr. DeSantis’s financial challenges.

“DeSantis is broke. How many more Gulfstream flights can he afford?” said Karoline Leavitt, a spokeswoman for Make America Great Again, a pro-Trump super PAC. (Ms. Leavitt was referring to Mr. DeSantis’s reliance on private planes to jet around to campaign stops, even after his operation was forced to cut costs.)

Staff turnover has been a constant in Mr. DeSantis’s runs for elected office, and he has had little overlap between any of the teams who have worked on his campaigns since he first became a congressman in 2012, people involved in his races have said.

Before his narrow victory for governor in 2018, Mr. DeSantis also shook up his campaign early in the race, when he was trailing Andrew Gillum, a Democrat, and struggling to hone his message.

Whit Ayres, a Republican political consultant who worked for Mr. DeSantis on that race but said he had not heard from the governor since, said that replacing staff could do only so much when the candidate himself might be part of the problem.

Mr. Ayres pointed to Mr. DeSantis’s comments about the Russian invasion of Ukraine being a “territorial dispute,” his suggestion that he might appoint the vaccine skeptic and Democratic presidential candidate Robert F. Kennedy Jr. to a top public health post, and his defense of Florida’s controversial educational standards on slavery.

“I’ve watched one unforced error after another,” Mr. Ayres said. “That suggests to me that he doesn’t have the political instincts to play at this level.”

Jonathan Swan contributed reporting from Washington.