WASHINGTON — Ronny Jackson, the White House doctor who rhapsodized about Donald J. Trump’s “incredible genes” and went on to win a Texas congressional seat with the former president’s help, cursed and belittled his subordinates, drank and took sleeping pills on the job, and sexually harassed a woman, according to a detailed report released Wednesday by the Pentagon’s inspector general.

Dr. Jackson, a rear admiral in the Navy when he served as White House physician, became infamous for his rosy assessment of Mr. Trump’s “excellent health” in early 2018, when he said that had the commander in chief, 71 at the time, simply adhered to a better diet over the previous two decades, he could have lived to be 200.

His effusive praise of Mr. Trump later helped win him a nomination to become the secretary of veterans affairs. But Mr. Trump abandoned the nomination several weeks later after numerous news accounts reported that Dr. Jackson was a bully to his staff, kept sloppy medical records, drank too much and loosely dispensed strong drugs on Air Force One and in the White House to curry favor with top officials.

With the endorsement of Mr. Trump, who tweeted that “Ronny is strong on Crime and Borders, GREAT for our Military and Vets,” Dr. Jackson went on to win a Republican primary in Texas and was elected to Congress in 2020.

On Wednesday, Dr. Jackson vehemently disputed the findings of the report. In a statement released by his congressional office, he accused the Pentagon’s investigators, who are nonpartisan, of seeking to punish him for his support of Mr. Trump.

The searing report, which came after a nearly three-year investigation started by Glenn A. Fine, the acting inspector general for the Defense Department at the time, went further than previous news reports. It concluded that “Jackson’s overall course of conduct toward subordinates disparaged, belittled, bullied and humiliated them,” and documented instances in which Dr. Jackson was drunk or under the influence of a powerful sleeping drug while he was responsible for the president’s health and safety.

The report also detailed evidence of what it said was Dr. Jackson’s harassment of a woman he worked with in the medical unit. In 2014, before a presidential trip to Manila as the physician for President Barack Obama, the report said Dr. Jackson told a male subordinate that he thought a female medical professional they were working with had a nice body, using coarse and demeaning language, and said he would “like to see more of her tattoos.”

While in Manila, witnesses said, Dr. Jackson went out for a night of drinking. After he came back to the hotel where the medical team was staying, they said, he began yelling and pounding on the female subordinate’s hotel room door between 1 and 2 a.m. while “visibly intoxicated.” Witnesses said he created so much noise they worried it would wake Mr. Obama.

“He had kind of bloodshot eyes,” the woman recalled to investigators. “You could smell the alcohol on his breath, and he leaned into my room and he said, ‘I need you.’ I felt really uncomfortable.”

“When a drunk man comes to your room and they say, ‘I need you,’ your mind goes to the worst,” she said.

The report, first described by CNN, painted a picture of a physician who engaged in reckless and sometimes threatening behavior that created a toxic environment for subordinates. Nearly all of the 60 witnesses interviewed by investigators described Dr. Jackson’s “screaming, cursing” behavior and his “yelling, screeching, rage, tantrums and meltdowns” when dealing with subordinates.

Investigators found that Dr. Jackson also engaged in inappropriate behavior on trips abroad with Mr. Trump.

In Argentina, a witness recalled that Dr. Jackson “smelled of alcohol” as he assumed his duties as the primary physician on the trip, and that the doctor had a beer a few hours before going on duty, in defiance of a policy prohibiting White House medical personnel from drinking on presidential trips. Dr. Jackson had previously recounted to witnesses that he found that rule to be “ridiculous,” investigators said.

Former subordinates interviewed by investigators raised concerns that Dr. Jackson took Ambien, a sleep-aid medication, to help him sleep during long overseas travel. Though it appears Dr. Jackson never was called upon to provide medical care after he had taken the drug, his subordinates worried that it could have left him incapacitated and unable to perform his duties.

In his statement, Dr. Jackson accused the inspector general of resurrecting “false allegations” because “I have refused to turn my back on President Trump.”

“I flat-out reject any allegation that I consumed alcohol while on duty,” Dr. Jackson said. “I also categorically deny any implication that I was in any way sexually inappropriate at work, outside of work or anywhere with any member of my staff or anyone else. That is not me, and what is alleged did not happen.”

In a fact sheet also provided to reporters, Dr. Jackson’s office noted that Mr. Obama had promoted him to rear admiral “after the alleged events” outlined in the report, and had profusely praised him for his work.

A spokesman for Mr. Trump did not reply to requests for comment on the report.

Former Obama administration officials declined to comment Wednesday on the report or Dr. Jackson’s behavior while he served as White House physician. In 2018, several aides to Mr. Obama said they were surprised by the revelations about Dr. Jackson.

Former White House officials said at the time that they had heard rumors about Dr. Jackson drinking, though all of them said they never saw him drunk on the job. But many said Dr. Jackson earned the nicknames “Candyman” and “Dr. Feelgood” for dispensing sleeping pills, muscle relaxants and other drugs with ease.

“I didn’t see any of the alleged behaviors,” David Axelrod, who served as Mr. Obama’s senior adviser from 2009 to 2011, said in spring 2018. “My experience was consistently positive.”

But the Pentagon report is unsparing in its details.

Investigators were told that Dr. Jackson “yelled and cursed over the telephone at a medical subordinate while the subordinate was dealing with a medical emergency in Africa.” During a trip to Martha’s Vineyard, where Mr. Obama often vacationed, Dr. Jackson “cursed at subordinates for failing to purchase a specific type of bug spray,” the report said.

“He would rage all the time,” one person is quoted anonymously in the report as saying about Dr. Jackson. “Screeching, red in the face, bug-eyed, sweating, ears red, jaw clenched. I mean I’m talking rage, and I’m a clinician. I’m a board-certified physician. Rage.”

Investigators for the inspector general’s office said in the report that officials in Mr. Trump’s White House tried to stonewall the investigation, instructing Dr. Jackson not to answer any questions about his time as White House physician and insisting on having White House lawyers sit in on interviews with anyone who was employed by the administration at the time.

“We determined that the potential chilling effect of their presence would prevent us from receiving accurate testimony,” investigators wrote in the report. Despite that, they wrote that interviews with former employees of the medical unit “and the documents we could access” were “sufficient to determine the facts and reach conclusions regarding these allegations based on a preponderance of available evidence.”

In April 2020, Mr. Trump pushed out Mr. Fine as he purged a number of inspectors general with whom he disagreed. A person familiar with the incident said the investigation into Dr. Jackson played a role in Mr. Fine’s dismissal.

Investigators were unable to corroborate accusations in 2018 by Senate Democrats that Dr. Jackson crashed a government vehicle after becoming intoxicated at a going-away party for a Secret Service agent. Dr. Jackson has consistently denied that he was ever involved in any accident involving alcohol, and the report said that “no information or witness testimony supported the allegation.”

Jennifer Steinhauer contributed reporting.