President Donald Trump announced on Friday that Stephen Miller, his deputy chief of staff, would replace Susie Wiles as chief of staff.
In a post on Truth Social, Trump said Wiles did an "outstanding job" and would be moved to the "Trump Political Operation".
The news comes after Republicans suffered a series of major defeats in the 2026 midterm elections, including losing control of both chambers of Congress.
Miller, considered the architect of Trump's hard-line immigration policy, has been a loyal ally of the president's and served as a senior adviser to Trump during his first administration. Trump said he would take on the new role on Monday.
In a statement, Wiles said being on Trump's team was "the honor of a lifetime".
"I'm so proud to have been a part of what we've accomplished together from securing our border and cutting taxes to strengthening our economy and putting America First," she said. "While my role may be changing, my commitment to the President and the mission never will."
Wiles, 69, is seen as among the most powerful figures in the Trump administration and someone particularly close to the US president.
Asked earlier this month whether Wiles could be replaced soon, Trump said there was "zero chance".
"Susie is here and she's gonna be here for a long time," he said.
Wiles recently battled cancer, announcing in September six months after her diagnosis that she was in remission.
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