5 things to know about Ronny Jackson, Trump's pick to replace Shulkin at the VA

President Donald Trump fired David Shulkin as Department of Veterans Affairs secretary last week and tapped White House physician Ronny Jackson as Shulkin's replacement. 

Trump praised Jackson as "highly respected" in his Twitter announcement, and White House Press Secretary Sarah Huckabee Sanders echoed the sentiment in a tweet of her own, saying that he and other cabinet nominees should be confirmed "without delay." 

However, veterans' groups expressed concern about Jackson's lack of experience in managing government agencies, let alone one the size of the VA. A former VA official told Politico that his "first reaction" to the announcement was "OMG." 

"[Jackson] has no experience," the official told the publication. "The VA is the hardest department to manage because it is so political." 

RELATED: VA announces 'aggressive' plan to improve quality at its low-performing hospitals 

Jackson's experience—or lack thereof—will certainly be a point of contention in his confirmation hearings. Here are a few more facts to know about Trump's pick to head the VA: 

Ronny Jackson
Ronny Jackson (U.S. Navy)

1. He has served in three presidential administrations.

Jackson first joined the White House medical staff in 2006 during the Bush administration, according to his Navy biography, and has directed the Executive Health Care for the President's Cabinet and Senior Staff. He was named Physician to the President by President Barack Obama in 2008, a role he continued under Trump. 

Jackson has also served as physician supervisor for the Camp David presidential retreat. 

2. Jackson is still an active duty soldier.

Jackson was serving in Iraq as an emergency physician and specializing in resuscitating troops when he was notified that he would be joining the White House Medical Unit. He began active duty naval service in 1995, according to his biography. 

The White House announced on March 23 that it had nominated Jackson for a promotion to rear admiral (upper half), which would make him a two-star admiral, CNN reported

3. He caught Trump's eye after announcing the results of the president's physical in January.

The president was impressed with Jackson's performance at a January press conference where he revealed the results of Trump's annual physical, CBS News reported. A source told CBS that Trump is also personally fond of Jackson. 

At the press conference, Jackson answered reporters' questions about Trump's health for more than an hour, saying that if the president had maintained a healthier diet over the past 20 years, "he might live to be 200 years old." 

4. His stance on key VA issues is an unknown.

Where Jackson stands on crucial issues at the agency he could soon command is not publicly known, according to Politico. This extends to privatizing the department's health system. Shulkin said that his opposition to VA privatization is the main reason he was pushed out. 

Jackson does have Trump's ear, though. Richard Tubb, M.D., the longest-tenured White House physician and Jackson's mentor, told CBS that White House doctors have been "figuratively Velcro-ed" to Trump since he won the election. 

"On Jan. 20, 2017, Dr. Jackson became that Velcro," Tubb said. 

5. Shulkin has praised his potential replacement 

Following his ouster, Shulkin didn't mince words about what it was like at the VA, writing in a New York Times op-ed last week that "the environment in Washington has turned so toxic, chaotic, disrespectful and subversive" that he struggled to accomplish his goals at the agency. 

However, he told ABC News that Jackson, despite his lack of experience, should be able to build a team around him that will allow him to succeed at the VA if he's confirmed. Shulkin told CNN that Jackson is a friend, and that he "will do everything that I can" to help him in the transition.