On Oct. 3, Navy Cmdr. Sean Conley said President Trump was not given supplemental oxygen to treat his coronavirus diagnosis. The next day, he backtracked. (Video: The Washington Post)

This spring, Navy Cmdr. Sean Conley confided to co-workers that he was laboring under intense personal stress in his job as White House physician.

The 40-year-old doctor is responsible for the world’s most high-profile patient: a president who has insisted on holding public events amid a global pandemic and rarely donned a mask, overriding the advice of his own health officials.

Without sharing details, the White House’s top medical officer said the pressures of the job were weighing on him, according to two people familiar with his remarks.

Conley now finds himself at the epicenter of the most acute crisis to confront a White House physician in decades: President Trump’s hospitalization after contracting a lethal virus whose risks the president has repeatedly minimized.

Conley’s handling of the situation has come under intense criticism after he gave a rosy pronouncement of Trump’s status Saturday without disclosing that the president had been given supplemental oxygen or put on a steroid reserved for severely ill coronavirus patients.

The White House physician finally disclosed those details Sunday, acknowledging that Trump’s oxygen level had dropped at one point. He said that he had not shared the information initially because he did not want to cause alarm.

“I was trying to reflect the upbeat attitude that the team, the president, over his course of illness, has had,” Conley said. “I didn’t want to give any information that might steer the course of illness in another direction. And in doing so, you know, it came off that we were trying to hide something, which wasn’t necessarily true. . . . The fact of the matter is that he’s doing really well.”

But long before the president contracted a virus especially lethal to older people, some of Conley’s former colleagues said they were disappointed in what they view as his lack of independence from White House politics.

“Every statement he is giving appears to be political, dictated by the White House or the president,” said one person who has worked with him, who, like others interviewed for this report, spoke on the condition of anonymity to avoid angering the White House. “These are not the statements a medical doctor gives.”

Conley did not respond to a request for comment. In a statement, White House spokesman Judd Deere said, “The fact that this publication has chosen to write a hit piece on the President’s physician, who is an officer in the U.S. Navy, at this critical time is outright disgusting and irresponsible.”

Deere added that Conley is an eminently qualified and “talented physician with a wealth of experience well-suited to serve President Trump and ensure he fully recovers from COVID-19 and remains very healthy to continue his work on behalf of the American people.”

National security experts describe a distracted and potentially vulnerable country

Questions about Conley began bubbling this spring when he treated Trump with hydroxychloroquine, an anti-malarial treatment touted by the president as a wonder drug, even as some studies showed it could increase the risk for some patients. In a May 18 memo, Conley said he concluded that “the potential benefit from treatment outweighed the relative risks.”

The White House has also repeatedly cited Conley in statements asserting that the administration was properly mitigating the risks of covid-19, the disease caused by the novel coronavirus, despite the fact that the president and his aides have eschewed masks and held public gatherings. In March, after a Brazilian official with whom Trump had posed for a photo tested positive, Conley issued a statement saying the president was at low risk and did not need to self-isolate or be tested.

And Conley has provided upbeat reports of the president’s health, despite the fact that Trump is 74 and clinically obese, echoing the kind of glowing assessments offered by his predecessor, Navy Rear Adm. Ronny L. Jackson. In a February 2019 memo, Conley wrote, “I am happy to announce that the President of the United States is in very good health and I anticipate he will remain so for the duration of his Presidency, and beyond.”

Former colleagues describe Conley as pleasant and collegial but said he lacks the extensive management experience that previous occupants of the job had.

After working as a Navy emergency physician and serving in a trauma unit in Afghanistan, he joined the White House medical unit in December 2016. Less than a year and a half later, he was tapped for the top job.

Conley replaced Jackson, whom Trump nominated to run the Department of Veterans Affairs in March 2018. Jackson was forced to withdraw from consideration weeks later amid an investigation into his workplace behavior.

At the time, Conley was the senior physician in the unit and served in an acting capacity as its head until the director of White House operations made the final recommendation that he be appointed to the position, a White House official said.

Conley is a doctor of osteopathic medicine, with similar training to medical doctors and the same authority to prescribe medicines. One key difference is osteopathic training also focuses on the relationship of the bones and the body and on treatment of the musculoskeletal system.

When he joined the White House, Conley found a mentor in Jackson, who took the Navy doctor “under his wing,” according to one former White House adviser, who noted both men had the shared experience of being emergency medicine doctors in the military.

The dynamics of Conley’s role in the military, like those of many of his predecessors, make it difficult for him to push back against Trump, former administration officials noted. As a Navy officer, Conley ultimately reports to the president and cannot defy an order from the commander in chief.

Some colleagues who have worked with Conley said they were alarmed by his upbeat description of the president’s status Saturday in a briefing outside Walter Reed National Military Medical Center.

“This morning, the president is doing very well,” Conley said. “At this time, the team and I are extremely happy with the progress the president has made. Thursday, he had a mild cough and some nasal congestion and fatigue, all of which are now resolving and improving at this time.”

He repeatedly dodged questions about whether Trump had received supplemental oxygen. A senior administration official later confirmed that Trump was given supplemental oxygen at the White House on Friday before going to Walter Reed.

Shortly after Conley spoke, White House chief of staff Mark Meadows told reporters that Trump’s “vitals over the last 24 hours were very concerning, adding: “We’re still not on a clear path to a full recovery.”

The conflicting accounts drove confusion about Trump’s status.

“Saturday’s briefing by President Trump’s medical team was a deliberate exercise in obfuscation, insulting to the public and unbefitting the seriousness of the moment,” Leana S. Wen, a visiting professor at George Washington University Milken Institute School of Public Health who served as Baltimore’s health commissioner, wrote in a Washington Post op-ed.

A White House official rejected the notion that Conley’s statements have been shaped by political considerations, saying he has never been pressured to say anything other than the truth.

Prospect of Trump’s early hospital discharge mystifies doctors

At Sunday’s briefing, Conley declined to answer questions about the president’s lungs, including whether there has been scarring or whether Trump has pneumonia. Trump’s medical team said he could be discharged as soon as Monday.

That surprised medical experts, who said he remains in the zone of a dangerous period of vulnerability. And they noted Trump is taking a five-day course of remdesivir, an antiviral therapy that is supposed to prevent spread throughout the body. Patients usually remain hospitalized throughout the course of treatment for monitoring, which would mean a patient in Trump’s situation would stay hospitalized until at least Tuesday evening.

Conley attended high school in Bucks County, Pa. He was a talented student and received “high honors,” according to the local Doylestown Intelligencer newspaper.

He attended the University of Notre Dame from 1998 to 2002, receiving a bachelor of science for preprofessional studies in science, a degree that sometimes leads to medical careers.

Conley then went to the Philadelphia College of Osteopathic Medicine, graduating in 2006. College officials did not respond to messages seeking comment about Conley’s studies.

He became a Navy emergency physician that year, working through a “transitional internship” at the Navy medical center in Portsmouth, Va., according to his LinkedIn page.

In 2007, he became a flight surgeon for Norfolk-based Helicopter Mine Countermeasures Squadron 14, serving for more than three years as a primary care physician for aviators and support crew. The squadron specializes in airborne mine countermeasures and heavy cargo delivery.

In June 2013, Conley began more training in emergency medicine at the naval medical center at Portsmouth. During his studies, he served for about six months at a multinational medical facility in Kandahar, Afghanistan, known as the NATO Role 3 hospital.

According to his LinkedIn profile online, he was a “departmental director.” Navy officials and colleagues of Conley did not respond to requests for more detail.

According to a July 2014 Army report, Conley was on assignment in Kandahar when at least six Romanian soldiers in Afghanistan were severely injured by an improvised explosive device. Some of them were medevaced to the NATO hospital. Conley and five others on the trauma team received a Romanian medal of honor.

“Lt. Cmdr. Sean Conley, a native of Doylestown, Pennsylvania, who serves as an emergency physician and department head of trauma for NATO Role 3 MMU, reflected on the team effort that took place that day,” the Army account said.

“It’s a reminder of the resiliency of the human body,” Conley said in the piece, “and it’s amazing what you can do when you have the right tools and the team that works with efficiency to make it happen.’ ”

Conley added: “It was the first time our team had seen a patient come in straight from the point of injury and only having tactical field care administered by a field medic. It was awesome to see how well the team reacted to a new situation.”

Conley finished his residency program in emergency medicine program in 2013, one of only eight graduates in the program that year, according to a Navy account. He received a few honors, including “The Nurses’ Choice Award” as an outstanding resident.

Before joining the White House, he served as research director at Portsmouth Navy Department of Emergency Medicine, according to the White House.

Clarification: An earlier version of this story erroneously implied that doctors of osteopathic medicine cannot be internists or general practitioners. In fact, a doctor of osteopathic medicine, like a medical doctor, can practice in every specialty area.

Alice Crites and Felicia Sonmez contributed to this report.