White House communications director Hope Hicks is resigning and will depart in the next few weeks, the White House says.
Hicks, who has been working with the president for three years, managed to stay in his orbit even after many others had been pushed out. President Trump called Hicks "outstanding."
"She is as smart and thoughtful as they come, a truly great person," Trump said in a statement on Wednesday. "I will miss having her by my side but when she approached me about pursuing other opportunities, I totally understood. I am sure we will work together again in the future."
News of Hicks' departure followed a day after she testified for hours before a closed session of the House intelligence committee. Lawmakers are investigating Russia's interference in the 2016 presidential election and whether any Trump campaign associates aided that effort. The White House has repeatedly denied any such collusion.
One person close to Hicks told NPR the resignation has been in the works for weeks and wasn't related to her testimony before the House intelligence committee or the broader Russia investigation.
The 29-year-old former model has had a knack for maintaining a low profile in recent years. She was often photographed with other White House aides but almost never spoke before microphones.
"I think it's a skill ... to avoid being in the press," Dana Perino, who served as White House press secretary during the George W. Bush administration, told NPR in August. "She is a true communications professional in that she doesn't seek the limelight."
That skill, along with her apparently unwavering loyalty, helped keep her in the president's good graces.
"She really understood the president's brand, that he's a mogul, that he's a magnet," said Sam Nunberg, who served as an adviser to Trump from 2011 to mid-2015. "And she said to me that people in the primary states were going to view him as a president because they watched him on The Apprentice. Which was true."
Hicks was serving as the White House's director of strategic communications when she was named interim communications director in August. That followed the days-long tenure of Anthony Scaramucci and the departure of multiple other communications directors — Sean Spicer, who had also been press secretary; Mike Dubke; and Jason Miller, who served during the transition.
Nunberg predicted at the time of her promotion that Hicks would be with Trump "to the very end."
Even so, on Wednesday the president's longest-serving aide said she too would leave.
"There are no words to adequately express my gratitude to President Trump," she said in a statement. "I wish the President and his administration the very best as he continues to lead our country."
This story has been updated.