President Donald Trump announced on March 5, 2026, that he is replacing Kristi Noem as Secretary of the Department of Homeland Security (DHS) with U.S. Senator Markwayne Mullin (R-Oklahoma). The change will take effect on March 31, 2026.

In a post on Truth Social, Trump praised Mullin as a "Highly Respected" senator and a "MAGA Warrior," highlighting his background as a former undefeated professional MMA fighter, his advocacy for tribal communities as the only Native American in the Senate (Mullin is a citizen of the Cherokee Nation), and his strong support for border security and America First policies. Trump stated that Mullin "will work tirelessly to Keep our Border Secure, Stop Migrant Crime... End the Scourge of Illegal Drugs and, MAKE AMERICA SAFE AGAIN."

Noem, who was confirmed as DHS Secretary in January 2025 following her nomination by Trump, will transition to a new role as Special Envoy for "The Shield of the Americas," a forthcoming security initiative focused on the Western Hemisphere. Trump thanked Noem for her service, noting her "numerous and spectacular results (especially on the Border!)."

The decision follows a turbulent period for Noem's tenure. Recent reports highlighted White House frustration after her congressional testimony, particularly a Senate Judiciary Committee appearance where she faced sharp questioning, including from Republican senators, over DHS decisions, including a costly advertising campaign and responses that reportedly displeased Trump. Broader controversies, including DHS funding fights, immigration enforcement challenges, and internal administration scrutiny, contributed to mounting pressure on her leadership.

Mullin, who has served in the Senate since 2023 after time in the House, has been a vocal Trump ally. He previously defended other Trump Cabinet nominees during confirmation processes and has emphasized tough stances on border security and government efficiency. His nomination requires Senate confirmation, though as a sitting senator and Republican in good standing, his path is expected to be relatively straightforward.

This shake-up reflects ongoing efforts within the Trump administration to align DHS leadership closely with priorities on immigration enforcement, border security, and combating illegal drugs and crime. Mullin's appointment signals a continuation (and potentially intensification) of those policies under new stewardship.