United States President Donald Trump has tapped his longtime adviser Stephen Miller to be White House chief of staff.

The move on Friday represented a doubling down on Trump’s most controversial policies following his Republican Party’s midterm drubbing earlier this week.

Democrats will take control of the US House of Representatives and Senate in January, and are widely expected to launch investigations into Miller’s role in the White House.

The 41-year-old Miller has been one of Trump’s most vocal defenders and is widely seen as an architect of the president’s mass deportation campaign.

In his post on Truth Social, Trump called Miller “one of my most trusted advisors”, saying he would take over the role from Susie Wiles on Monday.

An early adherent

Miller had built a reputation as a conservative activist long before entering Trump’s orbit.

At Santa Monica High School, he cut his teeth railing against what he described as liberal school policies on local radio shows.

At Duke University, he led the Duke Conservative Union and became a staunch advocate for three of the school’s lacrosse players after they were accused of rape.

After college, he moved to Washington, DC, where he worked as a legislative aide to Republican members of Congress and Republican Senator Jeff Sessions.

He joined Trump’s initial presidential campaign in January 2016, where he was credited with shaping the president’s messaging and caustic political stylings.

“I think he and Trump hit it off from the very beginning,” former Trump adviser Steve Bannon told The Associated Press news agency in 2017. “I think he helped Trump find his voice.”

What was his role during Trump’s first term?

Following Trump’s surprise victory in the 2016 race, Miller assumed the role of presidential adviser and speechwriter.

He served as an influential voice in shaping Trump’s most strident actions related to immigration, often framing the issues as an effort to protect Western “civilisation”.

During that period, Democratic lawmakers accused Miller of perpetuating white nationalist rhetoric. In 2019, the Southern Poverty Law Center released emails allegedly showing the Trump adviser supporting white nationalist websites and ideologies.

He is credited with shaping the Department of Justice’s 2018 “Zero Tolerance” policy at the US border, which called for the arrest of nearly every adult crossing into the US without legal documentation.

The scheme resulted in widespread family separation, with children barred from being housed in criminal detention facilities along with their parents. Trump later changed the policy via executive order, amid widespread outrage.

As an adviser to Trump, Miller campaigned to end Deferred Action for Childhood Arrivals (DACA), a programme that allowed individuals brought to the US as children without documentation to receive legal paperwork for education and employment. The programme stopped accepting new applicants in 2021.

Miller also drove wide-scale visa restrictions during Trump’s first term, including a 2017 travel ban on several Muslim-majority countries, which came to be known as the “Muslim travel ban”.

The initial order blocked citizens of Syria, Iran, Iraq, Libya, Somalia, Sudan and Yemen from entering the US for 90 days. An adjusted version of the policy was eventually upheld by the US Supreme Court.

He later became a top proponent of Trump’s unfounded claims that the 2020 election was stolen, supporting a scheme for Trump to be certified as the victor.

Trump 2.0

Miller remained by Trump’s side as the former president staged a political comeback ahead of the 2024 presidential vote. He became Trump’s deputy chief of staff for policy and homeland security adviser when the administration retook office in January 2025.

Since then, he has helped to orchestrate Trump’s mass deportation drive, which has seen immigration enforcement agents flood communities across the country, increasingly targeting individuals with no or only minor criminal records.

In May 2025, Miller told Fox News the administration had “set a goal of a minimum of 3,000 arrests for ICE every day, and President Trump is going to keep pushing to get that number up higher each and every day”.

He has also been a vocal defender of increasingly violent tactics by immigration agents. He initially defended the killings of Renee Good and Alex Pretti by immigration agents in Minneapolis in January. He initially called both Good and Pretti “terrorists” before walking back the statement about Pretti.

In his return to the White House, Miller also unsuccessfully sought to end birthright citizenship, while becoming an increasingly vocal defender of Trump’s military actions in the Western Hemisphere.

He endorsed the US abduction of Venezuelan leader Nicolas Maduro and told CNN in January that the US had a right to seize Greenland based on its military might.

“We live in a world in which you can talk all you want about international niceties and everything else, but we live in a world, in the real world … that is governed by strength, that is governed by force, that is governed by power,” he said.

“These are the iron laws of the world that have existed since the beginning of time.”

What does a chief of staff do?

It was not immediately clear how Miller’s new role would affect his influence over Trump.

The chief of staff is typically tasked with overseeing White House staff and hiring, maintaining the president’s calendar, and advising the president on policy.

Some insiders refer to the role, which largely controls information flows, as the “gatekeeper” to the presidency.