Senator Alan Armstrong of Oklahoma was born in McLennan County, Texas, on July 11, 1962. He graduated from Sooner High School in Bartlesville, Oklahoma, and earned a B.S. in civil engineering from the University of Oklahoma in 1985. Armstrong has worked as an engineer and held executive positions in the energy infrastructure sector. He served as chair of the National Petroleum Council in 2026 and was a member of the President's National Infrastructure Advisory Council. Appointed as a Republican to the United States Senate on March 24, 2026, he filled the vacancy caused by the resignation of Markwayne Mullin and took the oath of office on the same day.