Sanders' last briefing was 94 days ago, but Trump answers questions from reporters on a near-daily basis, including two extended sessions with them on Wednesday. "She is a special person, a very, very fine woman". I'll try not to get emotional.
Rumors had been swirling in June 2018 that Sanders would leave the White House at the end of that year. She is the daughter of former Arkansas governor and two-time presidential candidate Mike Huckabee and grew up with a fascination for politics.
Huckabee might have to defend herself as unlike her father, who fled Arkansas for income tax-free Florida after his tenure.
Several other press and communications officials have recently left the White House, where the president's mercurial nature has often made it hard to speak with authority on his behalf.
Sanders called the job "the honor of a lifetime".
Sanders' role had developed into that of a senior adviser and confidante of the president, one who is regularly brought into senior-level meetings.
Speaking with NBC News, Sanders did not say whether she would take another job in Arkansas or run for governor. She later corrected the error in a tweet.
The President, who was the one that recommended Sanders stop the daily press briefings, regularly praised her in private, bragging to others about how she defended him in television appearances and scuffled with the press.
Trump said he liked the idea. She notably stood in for him like a human shield after Trump's first major obstruction of justice controversy, the firing of FBI director James Comey, which Trump even admitted on TV was to stop the investigation into Russian election interference.
"You just said it's in the Bible to follow the law", Mr. Acosta challenged her at one point.
"The President urged me, like he has everyone in the administration, to fully cooperate with the special counsel".
The frequency of press briefings slowed down considerably after that day.
Donald Trump announced the departure via Twitter, the real press secretary.
Mrs Sanders hosted fewer news conferences than any of the preceding 13 press secretaries, according to the American Presidency Project.