Dr. Koff received his undergraduate degree from Hamilton College and his medical degree from Case Western Reserve University. He completed residency training in Internal Medicine at Brown University. He then completed fellowship training in Pulmonary and Critical Care Medicine at the University of California, San Francisco (UCSF). This included research in the Cardiovascular Research Institute in the laboratory of Jay A. Nadel, MD, and dedicated fellowship training in adult cystic fibrosis and lung transplantation. Dr. Koff joined the faculty at UCSF where he was associate director of the Adult Cystic Fibrosis Program and member of the Lung Transplantation Program. Dr. Koff joined the faculty at Yale University in 2011 to direct the Adult Cystic Fibrosis Program and to continue his research that focuses on pulmonary immunology. In 2018, Dr. Koff began a collaboration with Drs. Paul Turner and Ben Chan at Yale to develop phage therapy for CF and other diseases.