Gov. Ron DeSantis’s political orbit confronted fresh upheaval on the eve of Thanksgiving as the chief executive of the super PAC that has effectively taken over his presidential campaign resigned after days of infighting among DeSantis allies over strategy, financing and how to blunt the momentum of one of his rivals, Nikki Haley.

That chief executive, Chris Jankowski, sent a resignation note on Wednesday to the board of Never Back Down, which has been the main pro-DeSantis super PAC. The resignation was effective immediately. In a statement from Mr. Jankowski issued by the group, he described his differences with them as “well beyond a difference of strategic opinion.”

Never Back Down, which had amassed $130 million over the summer, has played a critical role in supporting Mr. DeSantis. Mr. Jankowski’s departure caps days of internal tensions within the group over the next steps in their Republican primary race against the front-runner, Donald J. Trump, and comes seven weeks before the pivotal Iowa caucuses in January.

Presidential campaigns are legally barred from coordinating with super PACs. But the DeSantis campaign and Never Back Down have repeatedly pressed the boundaries of what super PACs usually do.

Never Back Down has been paying for some of the candidate’s travel and striving to build a field operation across the country and in three of the early-voting states. Mr. DeSantis, who has lost significant ground in polling against Mr. Trump since before he became a candidate, routinely appears at fund-raisers coordinated by the super PAC and has traveled across Iowa on a super PAC-funded bus attending super PAC events as a “special guest.”

Mr. DeSantis has a long history throughout his political career of cycling through different teams, a fact that people who have worked for him have attributed to his micromanaging style.

In the statement from Mr. Jankowski provided by a Never Back Down spokeswoman, he said, “Never Back Down’s main goal and sole focus has been to elect Gov. Ron DeSantis as president. Given the current environment it has become untenable for me to deliver on the shared goal and that goes well beyond a difference of strategic opinion. For the future of our country I support and pray Ron DeSantis is our 47th president.”

In the past several weeks, allies of Mr. DeSantis and his wife have repeatedly complained about ads that Never Back Down ran attacking his closest rival in the primary, Ms. Haley, in connection with China. His allies have questioned the messaging and depth of the ad-buying by the super PAC, according to two people briefed on the matter. A third said some allies believed Mr. DeSantis was being blamed by voters for the negative spots.