Oklahoma Governor Kevin Stitt has appointed energy executive Alan Armstrong to fill the U.S. Senate seat vacated by Markwayne Mullin, who was recently confirmed as the new Secretary of Homeland Security. Armstrong, the chairman of Williams Companies, will serve in the Senate until the end of the year, completing Mullin's term.

Armstrong's appointment, announced on Tuesday (March 24), brings his extensive experience in the energy sector to the Senate. His expertise is seen as valuable during a time when the U.S. faces significant energy supply challenges.

Governor Stitt considered several candidates for the position, including his advisor Dustin Hilliary and oil baron Harold Hamm, but ultimately chose Armstrong.

Armstrong has a long history with Williams Companies, having joined nearly 40 years ago and served as CEO for over a decade before becoming chairman. His career has focused on expanding natural gas infrastructure across the U.S., and he has been a vocal advocate for balancing traditional and renewable energy sources.

Armstrong is required by Oklahoma law to sign an affidavit stating he will not seek election for a full six-year Senate term. The appointment is temporary, with the seat up for election in the next cycle.