Originally Published: 23 AUG 22 10:00 ET

Updated: 23 AUG 22 10:10 ET

By Phil Mattingly, CNN

(CNN) -- Inside President Joe Biden's tight-knit inner circle, few -- if any -- White House aides have spent more time by his side in the last three years than Stephen Goepfert. That will change at the end of this week.

Goepfert, Biden's personal aide, is set to leave the White House for a role at the Transportation Department, marking the departure of a key cog on Biden's team who has been by the President's side at every major moment since the first months of his 2020 presidential campaign.

"From the campaign to the White House, Stephen Goepfert has been by my side," Biden said in a statement. "In moments big, small, and extraordinary, he's been a trusted and loyal confidant who everyone counts on and who always delivers. Jill and I will miss Stephen, but we're proud that he will continue to serve the American people in his new role in the Biden-Harris administration as he continues his career in public service."

The first White House staffer Biden sees most mornings, and the last he sees nearly every night, Goepfert's tenure as Biden's "bodyman" was marked by a keen understanding of the cadence and details, both big and small, that drive a man who has been a public official for more than four decades, according to senior advisers.

While he may not be a household name, Goepfert is hard to miss -- he's the one with the beard in just about every Biden photo that includes staff, showing up on television to place remarks on the podium before a major Biden address or quietly emerging to slip Biden a note during a public event.

Goepfert will be succeeded by Jacob Spreyer, who currently serves as the official White House receptionist.

The role itself is all-consuming in any White House. It sits squarely at the nexus of the president's public and private lives and brings with it the demand for physical presence at nearly all times, whether at the White House, foreign trips or -- in Goepfert's case -- Biden's regular travel to his Delaware homes on the weekend.

"I have worked with and seen many body people over the years, Stephen is at the top," White House chief of staff Ron Klain said. "It's a tough and grueling job, and no one has done it with the competence, kindness, and warmth that he has."

The span of Biden's career brought with it a group of long-tenured -- and fiercely loyal -- senior advisers, many of whom joined him inside the West Wing. That group came to view Goepfert as a central piece of Biden's day-to-day life, and a trusted and loyal adviser in his own right.

"You're literally at the border of where the President's privacy and public duties sit -- you have to have the right touch and right skill set," Steve Ricchetti, the longtime Biden aide and confidant who serves as counselor to the President, told CNN. "Stephen has had the ability and the willingness to help the President navigate everything he did throughout the day. That ends up being a critical role."

Goepfert's emergence in Biden's inner sanctum was accelerated by the unprecedented challenge of holding the role on a presidential campaign in the middle of a once in a century pandemic -- a public health crisis that largely limited Biden to his Wilmington, Delaware, home for months.

Covid precautions limited Biden and his aides to remote contact for nearly his entire campaign. It was Goepfert who was physically there to help set up those Zoom calls, media interviews, tweak speeches and remarks, connect donor calls, put the briefing book together and finalize memos.

And, according to Annie Tomasini, one of the only other aides with regular physical access to Biden, do just about anything else required at the highest stakes moments of the campaign.

"You name it, Stephen did it," Tomasini, who has been with Biden for more than a decade and is now the White House director of Oval Office Operations. "I don't think people can quite grasp the pressures on him."

Goepfert's efforts resonated with Biden's senior team -- and Biden, a politician who close advisers have long said is energized and animated by personal connection, something sorely lacking in his pandemic environment.

Advisers would soon learn that Goepfert would come upon supporters -- sometimes running across them during the day, others through letters to the then-candidate -- and track down their phone numbers for Biden to call and maintain a connection.

"He understands that the President wants -- and that he's at his best -- when he's with the American people," Tomasini said.

It was practice he continued when Biden started to venture out in the later period of the campaign, ensuring the tried-and-true practice of photo lines dominated by politicians and donors included families that had sent letters to Biden.

"There is nothing that President Biden values more than authentic personal connection with people who he meets along the way," Ricchetti said. "How his personal aide treats other people alongside of him is vitally important as an expression of who the President is -- and Stephen is just phenomenal at that."

Goepfert's path to Biden's team started in the Obama White House, where he served as the deputy director in the Office of Presidential Correspondence. It was there Ricchetti, chief of staff to then-Vice President Biden took notice -- both of his writing skills and his personal nature -- and brought him over to serve as his senior adviser.

When Biden's former personal aide departed and the campaign was looking for a replacement, Ricchetti thought Goepfert, who he described as having a sharp sense of the ins-and-outs of how a White House operates from his tenure in the Obama administration, would be a perfect fit.

Goepfert would continue in the role when Biden took office in January 2021, becoming the first out gay personal aide to a president. It's a "first" that Goepfert has discussed with White House press secretary Karine Jean-Pierre, the first out LGBTQ person to hold her role.

"Representation matters and that's so important to him," Jean-Pierre said.

It's a close relationship that provided space for some levity and perspective at some of the most intense moments of Biden's first 19 months in office.

Tomasini recalled sitting silently in a presidential motorcade with Biden and his bodyman at a particularly high stakes moment on a foreign trip. Goepfert looked around and noted that it was quite a long way from the days in Wilmington when the trio had piled into Goepfert's car in a rush to make a train for a campaign trip.

Biden chuckled at the thought.

"He has a real humbleness that is just a real asset," Tomasini said.