Kristi Noem Replaced as DHS Secretary by Sen. Markwayne Mullin in Cabinet Move

Kristi Noem, the former governor of South Dakota who has served as U.S. Secretary of Homeland Security for the past year, was replaced Thursday by Oklahoma Senator Markwayne Mullin in a surprise cabinet move.

In a surprise announcement Thursday, March 5, 2026, it was revealed that Kristi Noem, who had served approximately one year as U.S. Secretary of Homeland Security — a cabinet-level position — would be replaced by Oklahoma Senator Markwayne Mullin.

Noem testified before Congress this week and, when asked by Sen. John Kennedy whether President Donald Trump knew about her spending approximately $220 million on an advertising campaign encouraging people in the country illegally to self-deport and then return by legal means, she said that he did.

However, while the President acknowledged he knew about an advertising campaign, he later denied knowing the particulars — including ads that featured Noem on horseback and the awarding of the contract to a close associate of hers. Kennedy said that after the congressional hearing, President Trump called him “as mad as a hornet” about the cost and the contract for the campaign.

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“Three strikes and you’re…”

That incident appears to have been the “straw that broke the camel’s back,” following several other recent controversies.

Among them was her reaction to protesters who lost their lives in Minneapolis, whom she initially labeled domestic terrorists before details about their identities were known. Her aggressive handling of immigration and deportation actions in major cities had also drawn steady criticism.

Also widely reported was an alleged affair with Corey Lewandowski, who had been serving as an advisor within DHS and is a longtime political ally of the President. Both Lewandowski and Noem are married to other people.

During her congressional hearing, she was asked in blunt terms whether she had ever had sexual relations with Lewandowski. She declined to answer directly, instead blaming a tabloid source for starting the rumors.

Eyebrows had previously been raised in South Dakota when Noem, while serving as governor, filmed a series of tourism and business-relocation television ads that were widely viewed as effective but prominently featured her at the center of the campaigns.

Enter Markwayne Mullin

Markwayne Mullin was asked to step in as DHS Secretary and accepted the request before even having time, he joked to the media scrum, to call “my wife or my dad.”

Mullin brings an unusual résumé to the cabinet post. He is the only current member of Congress without a bachelor’s degree, having taken over his father’s plumbing and construction business at age 20 when his father became ill. He later built multiple companies, competed as a professional MMA fighter, and is the father of six children. Mullin is also a citizen of the Cherokee Nation, making him one of the few Native Americans to serve in the U.S. Senate.

From 2013 to 2023, Mullin served as the U.S. Representative for Oklahoma’s 2nd Congressional District.

Before entering politics, he was a rancher, a professional MMA fighter, and owner of several companies focused on construction, plumbing, and home improvement. Mullin took over his father’s business at age 20 after his father became ill.

Mullin will step down as senator once confirmed for the DHS position. Under Oklahoma law, the governor will appoint a replacement who will serve until the next election.

Among the initiatives expected to continue under his leadership are finishing the border wall, emphasizing the “Remain in Mexico” policy, mandating E-Verify, and accelerating deportation proceedings.

Noem’s Major Accomplishments

During her tenure as head of the Department of Homeland Security — a role that also oversees the United States Secret Service — Noem is widely credited with helping dramatically reduce illegal border crossings.

Administration officials say that today the number of illegal crossings is near zero. They also cite approximately 1.9 million voluntary self-deportations and more than 650,000 formal deportations during the period.

In less than one year, under Noem’s management, the US met net negative migration, the first time since 1950 – seen as a full stop “pause” from the border while new policies and procedures are worked out and the 8 million illegal immigrants in the country over the previous administration are verified or deported.

With deportation of undocumented immigrants supported by majorities of Americans in both political parties, supporters argue that these accomplishments should not be overshadowed by the leadership controversies that ultimately ended her tenure.

What’s Next

Noem has been appointed United States Special Envoy for the “Shield of the Americas,” a new position tied to the President’s forthcoming Western Hemisphere security initiative expected to be announced later this week.

The Shield of the Americas is a proposed regional security partnership between the United States and several Latin American countries aimed at:

• Fighting drug cartels and narcotrafficking

• Stopping illegal migration toward the U.S.

• Increasing military, intelligence, and law-enforcement cooperation

• Coordinating security across the Western Hemisphere

A summit is expected this weekend in Florida with several regional leaders, including:

• Argentina: Javier Milei

• Chile: José Antonio Kast

• El Salvador: Nayib Bukele

• Honduras: Nasry Asfura

Thirteen heads of Latin American governments are expected to attend in total.

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Both Noem and Mullin addressed the announcement on social media platform X shortly after the news broke.