After serving on the faculty of Brown University for four years, Dr. Feinsilver served as Director of the pulmonary function laboratory and Sleep Center at Winthrop-University Hospital and later as Director of the division of Pulmonary, Critical Care and Sleep Medicine at North Shore University Hospital in Manhasset, New York, before moving to practice at Cardiovascular Medical Associates in March 2005.
In August 2011, Dr. Feinstein joined the faculty of Icahn School of Medicine at Mount Sinai as Director of the Center for Sleep Medicine.
Dr. Feinsilver has published more than 100 articles and book chapters, and edited a textbook on bronchoscopy. He is a Fellow of the American College of Physicians, the American College of Chest Physicians, and the American Academy of Sleep Medicine, and a reviewer for the journals Sleep, Sleep and Breathing, The Journal of Clinical Sleep Medicine, and Chest. He served as Governor for New York State for the American College of Chest Physicians from 2005-2009, and is now on the Steering Committee for the Sleep Section of the ACCP.