US President Donald Trump replaced chief of staff Susie Wiles with Stephen Miller on Friday, elevating the architect of some of his toughest domestic policies to run the White House after Republicans lost control of Congress in this week’s midterm elections.

The shake-up puts a longtime Trump loyalist and firebrand policy adviser in charge of steering Trump’s agenda as the president prepares to confront a Democratic-led House of Representatives and Senate, and an expected wave of congressional investigations.

White House officials told Reuters that Miller’s selection suggests Trump will take an aggressive approach to domestic policy and politics.

Miller is a veteran of Trump’s first term in office in 2017-2021. Since Trump’s return to the White House in 2025, Miller has officially been deputy chief of staff under Wiles, but he wielded outsize influence across much of Trump’s domestic agenda and has had the ear of the president.

He is perhaps best known for driving Trump’s aggressive immigration crackdown, setting a target of 3,000 arrests a day. In pursuit of that target, federal immigration agents expanded their list of targets to include migrants who had been living in the US for decades.

In a social media post, Trump called Miller “one of my most trusted advisers,” and he praised Wiles for doing “an outstanding job”.

Trump said the change would take effect on Monday.

Wiles, who submitted her resignation on Thursday night, will move to Trump’s political operation, according to a White House official.

Wiles, 69, who announced recently that she had been given the all-clear from breast cancer, said in a statement on X that Friday would be her last day in her job.

“Serving President Trump in the White House has been the honor of a lifetime,” she wrote.

“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.”

Trump had been displeased with his political and communications operations in the run-up to Tuesday’s election as his public approval ratings fell near record lows.

This week, he said the White House needed to be “more aggressive” as Democrats retake congressional power, according to a person briefed on the matter.

Wiles’ allies in the White House began sharing concerns with others on Wednesday about her potential replacement, the person said.

“He’s rewarding those most loyal to him. He’s not changing course,” said another White House official.