The Honorable Joseph S. Jewell, Ph.D., is the Assistant Secretary of War for Science and Technology (ASW S&T). As the principal advisor to the Under Secretary of War for Research and Engineering (USW(R&E)) on matters related to S&T, developmental prototyping, and experimentation he guides the Department’s science and technology strategy and investments, acting as a crucial link between fundamental scientific discovery and its strategic application in defense.

Dr. Jewell oversees and advocates for the entirety of the Department’s S&T enterprise, which includes its specialized workforce, laboratory infrastructure, Federally Funded Research and Development Centers (FFRDCs), and University-Affiliated Research Centers (UARCs). His office also directs a diverse portfolio of critical S&T programs including hypersonics and biomanufacturing. Basic research, the Small Business Innovation Research (SBIR) and Small Business Technology Transfer (STTR) programs, and the DoW Manufacturing Technology program, along with the nine Manufacturing Innovation Institutes (MIIs) also are within the S&T portfolio.

Prior to his current appointment, Dr. Jewell built a career at the intersection of academia and defense research. Most recently Dr. Jewell was the John Bogdanoff Associate Professor of Aeronautics and Astronautics at Purdue University in West Lafayette, Indiana where he served as Director of two hypersonic wind tunnels in the College of Engineering and the Purdue Applied Research Institute (PARI). Previously, Dr. Jewell was a research scientist at the Air Force Research Laboratory (AFRL). In these roles, his work centered on hypersonic aerothermodynamics, analyzing flight test data, and operating uniquely capable hypersonic wind tunnels. Dr. Jewell has authored more than 150 published journal articles and conference papers in aerospace engineering and hypersonics and holds a U.S. Patent in hypersonic inlet design.

Driven by a passion to secure America's technological future, Dr. Jewell is committed to strengthening the nation's future by preparing students for vital science and engineering careers in the Department of War, national labs, and the defense industry. His research has directly advanced U.S. military capabilities, having led hypersonic test programs for the Army, Navy and Air Force. Dr. Jewell has been a member or chair of four NATO Science and Technology Organization (STO) hypersonics working groups and was selected as a member of the Defense Science Study Group (DSSG) in 2024.

Dr. Jewell holds a Bachelor of Science in Aeronautics and History from the California Institute of Technology, a Master of Science in Engineering from the University of Michigan in Aerospace Engineering, as well as a Master of Science by Research from the University of Oxford in Engineering Science, where he was a Rhodes Scholar. Additionally, Dr. Jewell received his Doctor of Philosophy from the California Institute of Technology in Aeronautics. 

Dr. Jewell has received numerous awards including the NATO Panel Excellence Award, the National Institute of Aerospace Bo Walkley Best Research Publication Award, the Air Force Office of Scientific Research (AFOSR) Star Team Award (with R. Kimmel group, AFRL), the Office of Naval Research (ONR) Young Investigator Award and the NRC Research Associate Award. Dr. Jewell is a Fellow of the Royal Aeronautical Society (FRAeS), an Associate Fellow of the American Institute of Aeronautics and Astronautics (AIAA) and a registered Professional Engineer (PE, Michigan).

Dr. Jewell and his wife, Katie, have three young sons.