Dr. Kevin O’Connor, President Biden’s physician, has been mostly out of the public’s view despite first overseeing Biden's health care in 2009 and building what has been described as a cozy relationship with the Biden family over the last 15 years. 

"I have never had a better commander than Joe Biden," O’Connor said in a rare profile interview with his alma mater, New York Institute of Technology College of Osteopathic Medicine, when Biden served as vice president. "All politics aside, he approaches his craft with such honor. He’s 100 percent ‘family first.’ He’s ‘genuinely genuine.’"

O’Connor’s name, however, has recently become common in news reports, as speculation mounts that Biden’s mental acuity has slipped and concerns grow that the White House’s credibility regarding information on the president’s health is dwindling amid repeated gaffes, miscues and disjointed remarks Biden has made during public events. 

The White House physician is affectionately known to Biden and his family simply as "Doc," and was specifically requested by Biden in 2009 to stay on as his physician after serving on the White House Medical Unit under the George W. Bush administration. 

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President Joe Biden walking with White House physician Kevin O'Connor

President Biden, left, speaks with White House physician Dr. Kevin O'Connor as he arrives back at the White House in Washington, D.C., on Aug. 28, 2023. (Getty Images)

O’Connor was first appointed to the White House Medical Unit in 2006 for what was intended to be a three-year military assignment, according to his profile published by the New York Institute of Technology College of Osteopathic Medicine, from which he graduated in 1992. Instead, "Vice President Biden asked O’Connor to stay on," the profile continues. O’Connor complied, marking the beginning of their doctor-patient relationship that has reportedly evolved into a cozy relationship with the president’s large family. 

Beau Biden at podium in 2013

Principal Deputy Assistant Attorney General Stuart Delery, District of Columbia Attorney General Irvin Nathan, U.S. Attorney General Eric Holder, Iowa Attorney General Tom Miller, Deleware Attorney General Beau Biden and Illinois Attorney General Lisa Madigan hold a news conference at the Department of Justice Feb. 5, 2013 in Washington, D.C. (Chip Somodevilla/Getty Images)

Biden’s 2017 memoir "Promise Me, Dad," which was re-examined recently by Fox News Digital, features the president reflecting on his close relationship with "Doc," including O’Connor joining the family on their annual vacation to Nantucket, balking at the family’s "browsing extravaganza" on the tony island. 

The physician’s relationship with the family seemingly grew closer, according to the memoir, when the president’s son, Beau Biden, was diagnosed with brain cancer - which ultimately claimed his life in 2015. 

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"Doc was good with Beau, who was still trying to get his bearings in those first few days. Real fear was starting to creep in. Sometimes Beau would grab him when everybody else was out of earshot to get his honest assessment," Biden wrote in the memoir. 

"‘Whatever it is, this is bad,’ he told Beau, ‘but we’re gonna find out what it is. And once we find out what it is, we will have a plan.’" 

"‘Promise?’ Beau asked."

"‘Promise.’" 

In another excerpt, Beau Biden requested O’Connor "promise" to take care of his father if he should die. 

"‘Seriously, Doc. No matter what happens. Take care of Pop. For real. Promise me. For real,’" Beau Biden said to O’Connor, according to the book. 

Back in 2018, Biden’s sister-in-law, Sara Biden, described O’Connor as a "friend" who provided medical advice to members of the Biden family beyond the eventual commander in chief. 

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"Colonel O'Connor was actually a friend and he -- we would frequently ask for his recommendations if any of us had a medical issue, so it was not uncommon to ask him if he had a recommendation," she said in a deposition related to a New York state medical malpractice case involving her daughter.

Republican Texas Congressman Ronny Jackson, who served as former President Obama’s White House physician before also overseeing former President Trump's health, told the New York Post this month that Jill Biden has a cozy and familial relationship with O’Connor. 

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Ronny Jackson during WH press conference

Physician to then-President Trump, Dr. Ronny Jackson, speaks during the daily White House press briefing at the James Brady Press Briefing Room of the White House on Jan. 16, 2018 in Washington, D.C. (Photo by Alex Wong/Getty Images)

"Kevin O’Connor is like a son to Jill Biden — she loves him. It’s crazy. Kevin O’Connor was in that job on day one of the Biden administration because they knew they could trust Kevin to say and do anything that needed to be said or done and cover up whatever needed to be covered up. He is part of the Biden family," Jackson told the outlet. 

O’Connor, who retired as an Army colonel in 2017, also had a business relationship with the Biden family, Politico reported. He introduced Jim Biden, the president’s younger brother, to military health officials and met with another hospital president as the younger Biden pursued healthcare ventures through the hospital chain Americore in 2017, according to the outlet. 

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"I truly enjoyed our time together the other day," O’Connor wrote to a Pennsylvania hospital president after a meeting he shared with Jim Biden, according to Politico. "You and your team clearly share our vision, and I look forward to seeing you again in coming months." 

First lady Jill Biden departs from federal court

First lady Jill Biden departs from federal court, Wednesday, June 5, 2024 in Wilmington, Delaware. (AP Photo/Matt Slocum)

Concern over Biden’s mental sharpness hit a fever pitch late last month, when he delivered a botched debate performance that included losing his train of thought at times and giving garbled answers in a subdued and raspy voice. The debate unleashed panic among Democratic allies and members of the media, as they remarked his debate performance was a failure that added fuel to the fire surrounding concerns about Biden’s mental acuity and age. 

Amid the fallout from the debate, as well as his first sit-down interview with the media last week that did not help quell concerns, Biden has vowed to stay in the race. 

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"I want you to know that despite all the speculation in the press and elsewhere, I am firmly committed to staying in this race, to running this race to the end, and to beating Donald Trump," Biden wrote in a letter Monday to congressional Democrats, calling on them to end their questions on whether he should end his re-election bid.

Three shots of Biden during the debate

President Biden’s disastrous debate performance "changed people’s calculations about how candid they would be" about his cognitive issues, according to Olivia Nuzzi. (Photo by Justin Sullivan/Getty Images | Photo by Andrew Caballero-Reynolds/AFP via Getty Images | Photo by Justin Sullivan/Getty Images)

"I wouldn't be running again if I did not absolutely believe I was the best person to beat Donald Trump in 2024," he added.

The White House did not respond to Fox News Digital’s request for comment when asked about O’Connor’s close relationship with the president and the first family or whether the president would be evaluated by an outside doctor. Fox Digital also reached out to O'Connor through George Washington University, where he serves as associate professor of health, human function and rehabilitation sciences, but did not receive a response. 

As the White House and Biden campaign try to dismiss concerns over Biden’s debate performance, repeated gaffes and miscues while in public, the White House press corps has grilled the administration about the president’s health in increasingly fiery exchanges with press secretary Karine Jean-Pierre. On Monday, one White House reporter noted during the press briefing that the administration’s "credibility" regarding the president’s health has been called into question, while another reporter asked Jean-Pierre if the media could hear directly from O’Connor regarding Biden’s health. 

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O’Connor has never taken the podium at the White House to speak with the media, Fox News Digital found, including back in 2022, when Biden was diagnosed with COVID-19. 

Former White House doctor under the Trump administration, Sean Conley, spoke to the media when Trump was diagnosed with COVID in 2020, as did Trump’s previous physician Jackson in 2018 to tout the then-president’s "good genes" and how he passed a cognitive test. 

White House press secretary Karine Jean-Pierre

White House press secretary Karine Jean-Pierre speaks during the daily briefing at the White House in Washington, D.C., on Wednesday, Jan. 10. (AP/Susan Walsh)

O’Connor has released a handful of statements and updates on the president’s health since Biden was sworn into the nation’s highest office in 2021, including when he was diagnosed with COVID, as well as updates on Biden’s annual physicals. 

His interviews with the media and public events, however, are few and far between. O’Connor did have a sit-down, recorded conversation with the Federation of State Medical Boards in 2022, when he discussed his work in the White House and medical background, as well as another recorded interview with his alma mater last year. 

O’Connor has overwhelmingly brushed off media requests for interviews and comments in recent weeks, various media reports show, including when contacted by Fox News Digital since Biden’s disastrous debate performance on June 27. 

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Biden and O'Connor walk outside White House

President Biden walks along the Colonnade at the White House with his physician, Dr. Kevin O'Connor, on Aug. 28, 2023. (Manuel Balce Ceneta/AP)

The physician released his latest letter on Monday to address mounting concerns over reports showing a Parkinson's expert visited the White House eight times across eight months. 

O'Connor said Parkinson's specialist Dr. Kevin Cannard was chosen for Biden's annual physicals "not because he is a movement disorder specialist, but because he is a highly trained and highly regarded neurologist here at Walter Reed and across the Military Health System, with a very wide expertise which makes him flexible to see a variety of patients and problems."

The letter added that Biden did not see ​​a neurologist outside his annual physicals. 

No signs of neurological disorders, such as Parkinson's disease, multiple sclerosis, ascending lateral sclerosis, stroke or cervical myelopathy, were found during Biden's physical in February, O'Connor said. 

The Parkinson’s expert’s visits to the White House have fanned the flames surrounding the media’s concern that the White House has reportedly not been forthright with the public about the president’s concern. 

On Monday, during the White House press briefing, Jean-Pierre had a fiery exchange with CBS reporter Ed O'Keefe after brushing off questions regarding confirmation of Cannard's White House visits. 

"It's a very basic, direct question," O'Keefe shouted at Jean-Pierre. "That's what you should be able to answer by this point."

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"No, no, no, no, no," Jean-Pierre immediately pushed back. "Ed, please. A little respect here. Please."

"So every year around the president's physical examination, he sees a neurologist. That's three times, right? So I am telling you that he has seen a neurologist three times while he has been in this presidency. That's what I'm saying," Jean-Pierre continued. 

Karine Jean-Pierre at WH briefing room lectern

White House press secretary Karine Jean-Pierre fields questions from reporters during the press briefing at the White House in Washington, D.C., on July 8, 2024. (REUTERS/Evelyn Hockstein)

O'Keefe continued to press the matter, with O’Connor’s letter confirming Cannard’s White House visits later Monday. 

President Biden was pressed in an interview with George Stephanopoulos last week on whether he would take a cognitive test and release the results to the public, which Biden repeatedly dodged. 

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"Have you had the specific cognitive tests, and have you had a neurologist, a specialist, do an examination?" Stephanopoulos asked.

"No, no one said I had to. … They said I'm good," Biden responded.

Fox News Digital's Landon Mion and Joseph A. Wulfsohn contributed to this report.