The news comes a day after Hicks was interviewed for nine hours by the panel investigating Russia interference in the 2016 election and contact between Trump's campaign and Russia.
MORE: Notable firings, resignations under the Trump administration
Notable firings and resignations under the Trump administration
The panel pressed Hicks about whether she had ever lied for the president. Hicks eventually acknowledged to telling "white lies" for Trump but said she hadn't lied about anything substantial, including the Russia investigation.
Hicks served as Trump's one-woman communications shop during his winning campaign and has remained one of his most trusted aides.
In a statement, the president praised Hicks for her work over the last three years and said he "will miss having her by my side."
The Associated Press contributed to this report.