Dr. Crossley received his B.S. and M.S. degrees from the University of Georgia in Microbiology. He received his M.D. from the Medical College of Georgia in 1984. He served his internship, residency, and chief medical residency, cardiology and clinical cardiac electrophysiology fellowships at the University of Alabama at Birmingham.
He then joined the faculty of the Wake Forest University School of Medicine where he was an Assistant professor and then Associate Professor from 1991 to 1999. He then moved to Nashville and joined the practice that became St. Thomas Heart. There he served many senior administrative posts including the president of the group. In 2014 he joined the faculty of Vanderbilt University where he is a Professor in the Cardiology section.
He is active in clinical research, teaching and clinical medicine. Most of his research involves device therapy for arrhythmias. He has been a principal investigator of many research trials. He has been active in the governance of both the American College of Cardiology and the Heart Rhythm Society. He has lectured on 5 continents. He has been on the board of the International Board of Heart Rhythm Examiners since 1994. He served on the Board of Governors of the ACC and was also the president of the middle Tennessee chapter of the AHA.