Alan Armstrong

Alan Armstrong is Oklahoma's junior Republican senator, former CEO of Williams Companies, appointed in March 2026 to fill Markwayne Mullin's seat through the end of 2026.

Alan Stuart Armstrong is the junior U.S. Senator from Oklahoma, a Republican appointed in March 2026 by Governor Kevin Stitt after Markwayne Mullin resigned to become secretary of homeland security. Born July 11, 1962 in McLennan County, Texas, Armstrong was raised in Bartlesville, Oklahoma, and has never held elected office prior to his Senate appointment. A graduate of the University of Oklahoma with a degree in civil engineering, Armstrong spent nearly four decades with the Williams Companies, starting as an engineer in 1986 and eventually serving as CEO from 2011 to 2025. During his leadership, he oversaw the company's operations in natural gas infrastructure and energy transition initiatives. Armstrong was sworn in on March 24, 2026. Per Oklahoma law, he is ineligible to run for reelection and will serve only the remainder of Mullin's term through January 2027. His stated priorities focus on energy policy, particularly permitting reform to ensure Americans can access affordable energy solutions, and infrastructure development for economic growth and energy independence.