Prof. Hijazi is an interventional cardiologist who specializes in treating congenital and structural heart disease in both children and adults. He is a pioneer in the non-surgical repair of congenital and structural heart defects. 

Prof. Hijazi completed his postgraduate training from the Department of Epidemiology and Public Health at Yale University, where he was subsequently awarded a Masters of Public Health. He remained at Yale University where he completed a residency in pediatrics and a fellowship in pediatric cardiology. Upon completion of his fellowship training in 1991, he joined the faculty at Tufts University School of Medicine as an assistant professor. In 1997 he was promoted to Associate Professor of Pediatrics and Medicine, and in 1999 Prof. Hijazi accepted a faculty appointment at the University of Chicago as Endowed Professor of Pediatrics and Medicine and Chief of the Division of Cardiology. 

In 2007 Prof. Hijazi became the Director of the Rush Center for Congenital and Structural Heart Disease at Rush University Medical Center, Chicago and in 2010, he became the James A. Hunter, MD, University Chair. In January 2014, he became the inaugural chair of pediatrics at Sidra Medicine and in April 2021 became the chief medical officer.

Prof. Hijazi is very prolific with more than 360 peer reviewed published articles, nine books, over 60 book chapters and hundreds of abstracts. His major area of interest is in the development of techniques and catheters/devices to help treat or cure congenital and structural cardiac disease without open-heart surgery.

In 1997, he published the first results of the initial clinical use of the new Amplatzer septal occluder device for atrial septal defects (ASD) and performed the first case of ASD closure using the Amplatzer device in the US.