Ryan Jackson was a longtime aide to Sen. James Inhofe (R-OK), and most recently his chief of staff. — ProPublica

Bio, via Environmental Protection Agency:

Mr. Jackson joined EPA after nearly 20 years working in the U.S. Senate, first as counsel to the U.S. Senate Environment and Public Works Committee, and later as chief of staff to U.S. Senator James Inhofe (R-Oklahoma). As the staff director of the Committee, he coordinated a legislative and oversight plan for Chairman Inhofe that resulted in: the first long-term reauthorization of the nation’s surface transportation infrastructure in 10 years, the enactment of the Frank R Lautenberg Chemical Safety Act for the 21st Century (the first major federal environmental statute rewrite in 20 years), and a new Water Resources Development Act that prioritized funding for national ports and water infrastructure. In all, his leadership contributed to the enactment of over 60 statutes. While working in Congress, Mr. Jackson also worked closely with EPA on new state permitting for coal ash disposal and regulation, and on the reauthorization of the Brownfields program to promote beneficial use and new economic development for these areas. Previously, Mr. Jackson was an assistant district attorney in Oklahoma's 14th Judicial District, which covers Tulsa and Pawnee counties. A native of Oklahoma City, Mr. Jackson received his B.A. in public administration and political science from the University of Oklahoma, and his law degree from Oklahoma City University.