Stephen A. Harrison, MD, is the Medical Director for Pinnacle Clinical Research and the President of Summit Clinical Research.

He earned his medical degree from the University of Mississippi School of Medicine. He completed his internal medicine residency and gastroenterology fellowship at Brooke Army Medical Center and a 4th year advanced liver disease fellowship at Saint Louis University. He is board certified in both Internal Medicine and Gastroenterology.

Dr. Harrison served as a Professor of Medicine at the Uniformed Services University of the Health Sciences and is currently a Visiting Professor of Hepatology at the Radcliffe Department of Medicine, University of Oxford. He is a past Associate Editor for Hepatology and is currently an Associate Editor for Alimentary Pharmacology and Therapeutics. He is a peer-reviewer for more than 20 medical journals andisinternationally known for studies in hepatitis C and non-alcoholic fatty liver disease with close to 200peer reviewed publications in these fields.

Dr. Harrison most recently served as a Colonel in the United States Army. Retiring in 2016, he concluded 20 years of dedicated service to his country and served as the Director of Graduate Medical Education at Brooke Army Medical Center, Associate Dean for the San Antonio Uniformed Services Health Education Consortium and Gastroenterology Consultant to the Army Surgeon General.