Energy Executive Alan Armstrong Appointed to Mullin’s Senate Seat

Oklahoma Gov. Kevin Stitt appointed energy executive Alan Armstrong to the U.S. Senate seat vacated by Markwayne Mullin, who is set to become secretary of homeland security.

Armstrong will serve until a successor is elected in November. Under Oklahoma law, he is not eligible to run for the seat in the next election.

On March 24, Stitt, who had promised to appoint a “conservative voice,” selected Armstrong, the executive chairman and former CEO of Williams Companies, a Tulsa-based pipeline operator. Praising his choice, Stitt described Armstrong as “a strong business leader who understands the power of free markets and limited government.”

Although new to elected office, Armstrong brings decades of experience in the energy sector. He has spent his entire career at Williams Companies, which employs roughly 5,800 people and focuses on the collection, storage, and transportation of natural gas. He served as president and CEO from 2011 to last year, when he transitioned to executive chairman.

Armstrong is also a longtime supporter of Stitt, contributing the legal maximum of $8,500 to his campaigns since 2018.

The appointment comes amid a politically tense period for Stitt, who is set to leave office in January 2027 and currently chairs the National Governors Association. His decision follows a recent public dispute with President Donald Trump over attendance at the group’s annual meeting.

Former Tulsa Mayor Dewey Bartlett Jr. described Armstrong as “even-tempered” and inclined toward consensus-building rather than ideological decision-making. He also noted Armstrong’s deep knowledge of energy markets as a valuable asset, particularly amid global uncertainty affecting oil supplies.

Oklahoma’s other U.S. senator, James Lankford, welcomed the appointment.

“Congratulations to my friend Alan Armstrong on his appointment to serve our state in the United States Senate,” Lankford said in a statement.

“Markwayne leaves large boots to fill, but Alan’s strong background in energy and understanding of what powers our economy bring real-world experience at a critical time. I look forward to working with him to support Oklahoma workers, strengthen our energy independence, and keep costs low for families.”

Mullin, who was confirmed on March 23 to lead the Department of Homeland Security, would have faced reelection in November. With Armstrong ineligible to run for a full term, Trump has endorsed Rep. Kevin Hern (R-Okla.) for a full term.

In a post on Truth Social, Trump said Hern “is strongly supported by the fiercest MAGA Warriors in Oklahoma, and the most Highly Respected Leaders in the United States Senate!”

Trump said Hern is “doing a tremendous job” advancing the president’s America First agenda and that in the Senate, Hern will fight to grow the economy, cut taxes and regulations, keep the border secure, and more.

The Associated Press contributed to this report.