White House press secretary Sarah Huckabee Sanders will step down from her role next month.
US President Donald Trump confirmed the news in a pair of tweets.
He said: "She is a very special person with extraordinary talents, who has done an incredible job!
"I hope she decides to run for Governor of Arkansas - she would be fantastic. Sarah, thank you for a job well done!"
Mrs Sanders - the daughter of prominent Republican politician Mike Huckabee - has served as press secretary since July 2017.
Before that, she served a deputy press secretary, but took over the main role following the departure of her predecessor Sean Spicer.
She has become known for her often confrontational encounters with the press, echoing President Trump's complaints about "fake news".
She has also dramatically cut down on the amount of traditional White House press briefings - recently going more than two months without holding an on-camera briefing.
Some of Mrs Sanders' remarks to the press came under scrutiny in the recent report by special counsel Robert Mueller.
The report particularly highlighted her comments to the media that "countless members" of the FBI had spoken to the White House against James Comey, the former FBI director who was fired by President Trump in 2017.
Mrs Sanders later admitted to investigators it was a "slip of the tongue" - adding that her claim that rank-and-file FBI agents had lost confidence in Mr Comey was not founded on anything.
