President Trump has signed off on a plan to fire Dr. Marty Makary, commissioner of the Food and Drug Administration, after a series of clashes over vaping, oversight of the abortion pill and a series of new drug application denials that rattled biotech companies, according to a person briefed on the matter, who was not authorized to discuss it publicly.

Dr. Makary had a high profile for an F.D.A. commissioner, appearing frequently on television and podcasts to sell the work he was doing at the agency on improving the food supply, speeding up some drug approvals and trying to restore agency morale after thousands of staff members left.

He tried to walk the tightrope between the business-friendly Make America Great Again movement, pledging to get rid of regulations that slow down innovation and to attract more drug trials to the United States. He was an ally of Health Secretary Robert F. Kennedy Jr.’s Make American Healthy Again supporters, voicing the skepticism of the pharmaceutical industry and authorizing natural food dyes.

Ultimately, Dr. Makary’s efforts were not enough to overcome the grievances of a growing band of enemies focused on selling tobacco, opposing abortion and seeing biotech therapies authorized.

Mr. Trump’s decision to dismiss him was first reported by The Wall Street Journal.

The decision could still change, given Mr. Trump’s propensity to change his mind Dr. Makary has also proven persuasive with Mr. Trump in beating back previous efforts to oust him.

Leaving the White House Friday evening, Mr. Trump dismissed the idea that Dr. Makary would be fired.

“I’ve been reading about it, but I know nothing about it,” he said.

The White House has pressured Dr. Makary for months to authorize flavored e-cigarettes, according to a person close to the conversations. The approvals were a top wish of major tobacco companies that have been top donors to Mr. Trump. In March, the F.D.A. issued a memo saying that it would only authorize e-cigarettes in flavors such as mint, tea and spices. The memo said the fruit and candy flavors would be unlikely to pass muster, given their appeal to young people.

Pressure continued, though, and on Tuesday the F.D.A. authorized blueberry and mango flavored e-cigarettes by Glas, a small company based in Los Angeles.

Abortion foes including Susan B. Anthony Pro-Life America have continued to turn up the heat on Dr. Makary, reiterating their call for his firing on Thursday. The group’s leaders and others view Dr. Makary as dragging his feet on a safety review of the abortion pill mifepristone, which they viewed as a way to highlight what they believe are dangers of the drug. Former Vice President Mike Pence, who also opposes abortion rights, amplified criticism of Dr. Makary on social media as well.

The administration has been under pressure from conservatives to tighten regulations on the prescribing and dispensing of mifepristone. The Supreme Court is reviewing a federal appeals court ruling that temporarily blocked abortion providers from prescribing the drug through telemedicine and sending it to patients by mail.

Biotech companies and their investors have also raised alarms with the White House about agency decisions to reject a series of treatments for rare diseases. The F.D.A. typically turns down about 20 percent of the applications it receives for drug approvals from companies.

Dr. Makary has been aggressive in defending the decisions, which he said came from career scientists who found the medications ineffective.

Dr. Makary also had to contend with a health secretary who seemed to view the F.D.A. as an avenue for getting his favored products authorized, exemplified by Mr. Kennedy’s social media post saying that the agency would end its “war on” stem cell treatments, peptides and raw milk. Mr. Kennedy pushed the F.D.A. to reverse a 2023 ban and allow the use of a number of peptides, unproven compounds purported to offer anti-aging or muscle-recovery benefits.

Before leading the F.D.A., Dr. Makary was a cancer surgeon and health policy researcher at Johns Hopkins University School of Medicine. He was also the author of several books about the health care system.

Some of Dr. Makary’s more popular moves included encouraging broader use of hormone replacement products for women and lifting the F.D.A.’s warnings on them. He helped speed some promising drugs to market, including a pancreatic cancer therapy and the pill form of the popular GLP-1 weight loss drugs.