Trump to fire DHS Secretary Noem, picks Mullin as successor

Kristi Noem will step down as secretary of the Homeland Security Department at the end of the month, President Trump announced on Thursday, amid a tumultuous period for the agency that has overseen the administration’s controversial immigration crackdown. 

Trump said on social media that he will nominate Sen. Markwayne Mullin, R-Okla., to replace her. He suggested the change would take effect March 31, though the DHS secretary requires Senate confirmation and the timing for such a vote is not yet clear. The White House did not immediately respond to a request for clarification. 

DHS is currently shut down after its funding lapsed last month, though more than 90% of its employees are still working. Many of those are doing so without immediate pay. 

Noem’s firing came after she testified in Congress on back-to-back days this week, where she faced pointed questions from members of both parties on the fatal shootings of U.S. citizens by DHS employees, the aggressive tactics used in immigration enforcement, and the spending on a contract for advertising in which the secretary was featured prominently. Noem said Trump personally signed off on that spending; on Thursday, the president denied it. 

Noem also presided over a rapid hiring surge at the department, focused primarily on Immigration and Customs Enforcement and Customs and Border Protection. ICE more than doubled its workforce in 2025, when it brought on more than 10,000 employees. The One Big Beautiful Bill Act that Trump signed into law last year provided $165 billion for DHS, including $16 billion for staffing. 

Mullin began serving in the House in 2013 and in the Senate in 2023. Trump called him a “MAGA warrior” and said the senator “knows the wisdom and courage required to advance our America first agenda.” 

“Markwayne will work tirelessly to keep our border secure, stop migrant crime, murders and other criminals for illegally entering our country, end the scourge of illegal drugs and make America safe again,” Trump said. “Markwayne will make a spectacular secretary of Homeland Security.” 

Trump said Noem will become special envoy for the Shield of the Americas, an upcoming conference on Western Hemisphere security.