 After completing his residency in medicine at the University of Chicago, he taught and practiced clinical medicine at the University of Illinois Medical College, where he began his research in the etiology of cardiovascular diseases (1950–67).He survived a near-fatal episode polio in 1954 and started a private clinical practice and that year in the western Chicago suburb of Hinsdale, Illinois, serving the local community as a cardiologist and family practitioner and also continuing his research part-time at the University of Illinois and the Chicago Heart Association.He returned to full-time teaching and academic research at Rush Medical University in 1967.