Dr. Slagle graduated Alpha Omega Alpha from the University of Oklahoma in 1969 and completed his Internal Medicine residency and Cardiology fellowship at Duke University Medical Center before entering the private practice of cardiology in Tulsa, Oklahoma. In 1986, he was elected the first President and Chairman of the Board of the PHO for Saint Francis Hospital. While Chief of Staff from 1989 to 1990, he initiated the Medical Staff Credentialing Committee and the Professional Affairs Committee of the Board for the hospital.

In 1993, after 20 years of interventional cardiology practice, Dr. Slagle left his position as President and Managing Physician of Cardiology of Tulsa, Inc. to become a full-time physician executive as Medical Director for the hospital and has since earned a Master's degree in Medical Management from Tulane University and the American College of Physician Executives. His management interests include physician leadership and quality of health care delivery based on health system redesign. He was responsible for the initiation of multiple service lines for the Health System as well as the system credentialing organization. Paired with the Chief Operations Officer, he had operational responsibility for the hospital division of the Health System, which consisted of Saint Francis Hospital, the largest hospital in Oklahoma, Laureate Psychiatric Clinic and Hospital, and Saint Francis at Broken Arrow, a small suburban hospital. In January 2000, Dr. Slagle returned to the private practice of cardiology. Currently, he also serves as the Medical Director and Chief of Staff for the Saint Francis Heart Hospital, an all digital specialty hospital that is a joint venture between the Saint Francis Health System, the Warren Foundation, and numerous Cardiovascular Practitioners in Northeastern Oklahoma.

Dr. Slagle first received a degree in Electrical Engineering and worked as a control systems engineer on the Apollo project. He subsequently taught inertial guidance systems for the Army Missile School for two years before going to medical school. He is board certified in Internal Medicine and Cardiovascular Disease and is a Fellow in the College of Physicians as well as the College of Cardiology. He served as the Governor of the College of Cardiology for Oklahoma from 1993 to 1996, serves on the clinical faculty for the University of Oklahoma Medical School at Tulsa, and was President of the Tulsa Medical Education Foundation from 1998 to 2000. For the last seven years, he has served on the faculty for HortySpringer Seminars for Medical Staff Leaders.