Lewis A. Conner, MD (1867 to 1950), was a pioneer in public health cardiology, cardiac rehabilitation, and cardiac psychology. He helped establish the Burke Rehabilitation Hospital and was the founding president of the New York and American Heart Associations (AHA). Dr Conner was the founder of the American Heart Journal, America's first medical subspecialty journal, and the official publication of the American Heart Association until 1950, when CIRCULATION: was created. Conner spent more than a half-century on the staff of the New York Hospital and Cornell University Medical College and was Chairman of Medicine from 1916 to 1932. During this time, he created the innovative Cornell Pay Clinic and united the "old" New York Hospital with the new and scientifically-oriented Cornell University Medical College on a modern and inspiring urban campus. An extraordinary clinician and a humanist with great equanimity, Conner devoted his career to the Oslerian tradition of scholarship, leadership, and organization in the quest for improved patient care. This article contains newly discovered biographic material on Dr Conner and explores his professional and personal connection to Sir William Osler.