Sen. Markwayne Mullin (R-Okla.) is set to step into the spotlight as he readies to take on the unexpected challenge of replacing Kristi Noem atop the Department of Homeland Security (DHS), culminating a swift rise from the House to one of the key posts in the Trump administration.

Leadership and Reputation

In a matter of years, Mullin has seen his stock rise exponentially from being a rank-and-file House member to being a key part of Senate Majority Leader John Thune’s (R-S.D.) leadership team. Lawmakers across the party have hailed him as a consummate teammate and leader, something they believe the beleaguered department needs badly.

“He’s the sort of person who knows what he doesn’t know. That was the problem with Noem. She couldn’t scale her experience, and I think he can,” said Sen. Thom Tillis (R-N.C.), likening him taking over at DHS to an NFL team getting the first overall pick of the draft and becoming a Super Bowl contender a year later. “There’s nowhere to go but up.”

Political Alliances and Background

Sen. Katie Britt (R-Ala.), who was elected alongside Mullin as part of the 2022 class, called him “a visionary and a workhorse.”

“There’s nothing that’s too big for him to tackle,” Britt said in an interview. “He’s built solid relationships with people on both sides of the aisle. He’s going to keep his word. He’s loyal, and he’s straightforward and pragmatic in his approach.”

Mullin is ready to take over a department that is at the center of a storm of controversy over how the administration is carrying out its immigration agenda and has been shut down for weeks as Democrats and Republicans battle over reforms to Immigration and Customs Enforcement (ICE).

The Oklahoma Republican got the call to head up DHS during lunch on Thursday, with one senator noting that he left a full plate of food in front of him. The Oklahoma Republican later told reporters that he found out about the nomination “a little bit before you guys did” and that it came as a surprise to him.

GOP lawmakers, on the other hand, are not surprised to see Mullin get the nod. A close ally of Trump, Mullin has been one of the president’s top block-and-tacklers in the upper chamber dating back to his campaign.

He is also viewed as a savvy operator and a member that others want on their side. On top of being close to Trump, Mullin is close friends with Vice President Vance, having been part of the same 2022 Senate freshman class. Mullin was one of Thune’s foremost backers during his run for majority leader in 2024 and has served on his leadership team throughout the 119th Congress.

The Oklahoma Republican is part of Sen. John Barrasso’s (R-Wyo.) whip team and was recruited by Sen. Susan Collins (R-Maine) to join the Appropriations Committee. Mullin is also an ally of Speaker Mike Johnson (R-La.) and was a top backer of former Speaker Kevin McCarthy (R-Calif.).

Personal Relationships and Influence

Allies on Capitol Hill say that this phenomenon is no accident. “He engages in the issues and the ideas, and connects people. That’s what he does, and he does really, really well,” Sen. James Lankford (R-Okla.), who served alongside him in both chambers, said in an interview. “He has no problem talking to people that do not agree with him or do not agree with each other in trying to find a way for them to talk it out and to be able to figure it out.”

“People see him as this pugnacious fighter, which he clearly does have strong beliefs and is going to go fight for his beliefs and his values,” he continued. “But he also has a core value that is a faith-driven value of ‘I need to talk to everybody, and everybody needs to talk to everybody as well and we can figure this out.'”

That nature was on display years in his relationship with Sean O’Brien, who Mullin challenged to a fight during a 2023 hearing before the Senate Health, Education, Labor and Pensions (HELP) Committee. Months after the incident, the two ended up mending fences, with O’Brien praising his nomination on Thursday.

“If anyone is willing to stand their butt up to protect America, it’s Markwayne Mullin,” O’Brien said in a statement, referencing Mullin’s line during the hearing for the Teamsters chief as they readied to drop the gloves.

Supporters also describe a lawmaker who is not only connective tissue inside the Senate, but also someone who has a finger on the pulse of the House. He was frequently seen attending House GOP conference meetings, especially during his first two years in the Senate.

“I know it sounds kind of crazy, but people weren’t doing that before him,” former Sen. Kyrsten Sinema (I-Ariz.) — a longtime friend and former workout group participant, dating back to their House days — said about his informal House liaison work.

Sinema also noted that after she became an independent and prior to her decision not to seek reelection, Mullin allowed her to use his townhouse on Capitol Hill to make fundraising calls as she was no longer able to do that from the Democratic Senatorial Campaign Committee and needed a place away from the Capitol complex.

Challenges Ahead

There are some minor headwinds facing Mullin’s nomination, though nothing that is expected to seriously gum up the process. His confirmation hearing will take place before the Senate Homeland Security and Government Affairs Committee, which is chaired by Sen. Rand Paul (R-Ky.). Mullin recently told a group in his home state that Paul is “a freaking snake” and sympathized with the neighbor that attacked the Kentucky senator in 2017.

Paul declined to comment on the nomination on Thursday when asked by The Hill. He is also tasked with convincing members of a Democratic caucus who are locked in an ongoing battle with the administration over ICE tactics. Senate Minority Leader Chuck Schumer (D-N.Y.) told reporters that the issues at DHS “transcends any one individual.”

“This is a problem of policy, not personnel,” he said. “The rot is deep. No one person can straighten this up until the president changes the whole agency, stops the violence, and reins in ICE.”

Yet, some Democrats are keeping the door open to supporting him. Sen. Chris Coons (D-Del.) told reporters that he “would consider” backing him on the floor, but vote is contingent on him making “real changes” on immigration enforcement.

Mullin also got a key vote right out of the gate as Sen. John Fetterman (D-Pa.) announced that he will vote for him to become secretary, hailing him as a “good dude.” The early show of support is also important at the committee level as Fetterman sits on the Homeland Security panel and would provide a Democratic vote if Paul or another Republican were to vote “no.”

Personal Life and Routine

Although Mullin’s title is likely to change in the coming months, lawmakers predict that one thing will not be altered: his workout routine. The Oklahoma senator, who is a former mixed martial arts fighter, is well known for his early-morning workouts that members describe as challenging and disciplined.

“He’ll just get up earlier,” Lankford said laughing. “If he’s not working out, he gets lethargic.”