Alongside the announcement of Noem’s ouster, Trump said he would tap Sen. Markwayne Mullin, R-Okla., to replace her, elevating a fiercely loyal first-term senator.

“I am pleased to announce that the Highly Respected United States Senator from the Great State of Oklahoma, Markwayne Mullin, will become the United States Secretary of Homeland Security (DHS), effective March 31, 2026,” Trump wrote on Truth Social.

He added that Noem, who he said “has served us well,” will take over a new role called “Envoy for The Shield of the Americas.” He described the position as one that will lead “our new Security Initiative in the Western Hemisphere.”

Trump spoke to Noem about the job switch Thursday afternoon, according to two people familiar with the conversation. Noem is traveling outside Washington.
An administration official told NBC News that Trump decided to fire Noem because of “a culmination of her many unfortunate leadership failures including the fallout in Minnesota, the ad campaign, the allegations of infidelity, the mismanagement of her staff, and her constant feuding with the heads of other agencies, including CBP and ICE.”