J.D. Polk, DO, MS, MMM, CPE, FACOEP, is the principal deputy assistant secretary for Health Affairs and deputy chief medical officer of the DHS. He has served as the deputy chief medical officer and chief of space medicine for NASA’s Johnson Space Center, an assistant professor at the University of Texas Medical Branch, Ohio EMS medical director and chief of Metro Life Flight in Cleveland. He received his degree in osteopathic medicine from the A.T. Still University in Missouri. He holds a master’s degree in science in space studies from the American Military University and a master’s degree in medical management from the University of Southern California.