In November 2011 he was appointed by New York State Governor Andrew M. Cuomo to serve as Commissioner of the Division of Homeland Security and Emergency Services. 

Department of Health and Human Services (HHS) Secretary Tommy G. Thompson named Hauer as the first Acting Assistant Secretary for the Office of Public Health Emergency Preparedness in 2002.  During his tenure, Hauer was responsible for coordinating the country’s medical and public health preparedness and response to emergencies, including acts of biological, chemical, nuclear terrorism, and other public health emergencies.

In 1996, Hauer was named first Director of the Office of Emergency Management for the City of New York by Mayor Rudolf Giuliani.   New York became the first city to develop a bioterrorism response plan and to do large-scale bioterrorism exercises.  Hauer and his staff in New York City also developed the concept of 

 He is a Visiting Professor at the Defence Academy of the United Kingdom/Cranfield University He was an assistant professor in the School of Public Health & Health Services and the School of Medicine at George Washington University.

Dr. Hauer is currently an Associate Editor of the Journal of Special Operations and on the Board of Directors of the World Association for Disaster and Emergency Medicine.

Hauer developed the first technique for re-infusing blood lost by patients following cardiac surgery while a graduate student at Johns Hopkins. He served on the faculty of the Northeastern University Paramedic Program and was a teaching assistant in the physiology labs for first-and fourth-year students at Harvard Medical School. He has coauthored forty-six (46) publications, a book, and two (2) monographs.