During his 20-year tenure at Cornell, he published over 45 peer-reviewed scientific papers, presented findings in numerous local, national, and international medical conferences, served as a frequent lecturer and visiting professor in addition to have developed a large clinical practice that is one of the busiest (400 to 625 major cases per year) in the New York metropolitan area. In 2006, Ko was recruited to be the professor and chief of cardiothoracic surgery at the State University of New York—Downstate University Medical Center in Brooklyn, where he formed and presided a new multidisciplinary team with aims for a center of excellence. During this three-year tenure, he recruited a new team including two cardiothoracic surgeons, chief intensivist, chief physician assistant, chief perfusionist, nurse practitioners, data manager, researcher, and office staff; this team remains intact today. In this challenging institution, Dr. Ko revitalized clinical services, added new surgical programs, improved the training program of fellows, general surgery residents and medical students, and initiated research projects including one that was awarded NIH funding. In his departure, he was given the University President’s Best Teacher Award by the graduating class of over 1,000 residents, fellows, and students in 2009. In 2009, Ko was recruited to form the new Department of Cardiothoracic Surgery and became its chairman at the St. Vincent Hospital Manhattan, a major teaching affiliate of New York Medical College where he is appointed Professor of Surgery The goal was to build a world-class cardiovascular center with the latest techniques and technology to serve the residents in the five boroughs of New York City. The new department was formed with 3 cardiac surgeons and 2 thoracic surgeons with case volume more than doubling over the first six months. Unfortunately, the hospital went into bankruptcy and closed in April 2010 due to a disastrous financial situation. Currently, he serves as attending cardiothoracic surgeon and the co-director of Asian Cardiac Center at Beth Israel Medical Center. Ko had been a visiting professor in the First Municipal Hospital of Guangzhou (Canton, China) for three consecutive years, where he gave lectures and performed surgeries to demonstrate the modern American techniques in heart surgery. Subsequently, he had received surgeons from that hospital for advance training at New York Hospital of Queens. In August 2009, initial discussion has begun to consider a teaching interchange between St. Vincent Hospital Manhattan and First Affiliated Hospital of Guangzhou Medical College in China