The promotion of Jackson marks the latest Trump hire to be driven at least as much by personal familiarity with the president as by his vision for the role.
In Shulkin's place, Trump nominated White House physician Ronny Jackson, an active duty Navy admiral with no experience managing a federal agency.
Dr Jackson has served since 2013 as the physician to the president, and gained a national profile earlier this year for holding a sweeping press conference on the president's health.
Shulkin had continued to insist he had the full confidence of the White House amid continuing investigations into his travel and leadership of the department.
AMVETS Executive Director Joe Chenelly questioned whether Jackson, who has no experience in management, is qualified to run a $200 billion a year bureaucracy, the second largest agency in the United States government.
White House officials said Shulkin had become a distraction as a result of the speculation surrounding his future. This is evidenced by the administration's hiring of Darin Selnick to the White House's Domestic Policy Council.
Trump has told aides and outside advisers that he is fond of Jackson personally, according to a person familiar with the president's thinking but not authorized to discuss private conversations. At the briefing, he pronounced Trump's health "excellent" and dismissed questions regarding Trump's mental fitness by saying he had "no concerns" in that area.
During the briefing, Jackson spent almost an hour exhausting reporters' questions, extoling the president's "incredible genes" and joking that if only Trump had eaten a healthier diet over the last 20 years, "he might live to be 200 years old". But according to a Wednesday report from Axios' Jonathan Swan, President Trump is far more concerned with another pillar of big tech: Amazon.
In January 2017, Trump appointed Shulkin as Veterans Affairs secretary and said, "He's fantastic". He later became an honor graduate of the Navy's Undersea Medical Officer Program in Groton, Connecticut. In 2005 he deployed in support of Operation Iraqi Freedom as emergency medicine physician with a surgical shock trauma platoon in Taqaddum, Iraq. "I think he wants to do the right thing and will work hard to do that, and I will personally help him in any way possible".
What Jackson knows about the VA or running a large organization is to be determined. Sen. Lindsey Graham (R) or SC. But veteran affairs groups, which exert an unusual degree of influence in Washington, DC, supported Mr Shulkin because they considered him a bulwark against the creeping privatisation of veterans' health-care services (which are now operated through a single purchaser which owns its own facilities and employs its own doctors).