She receieved her undergraduate degree from the University of Notre Dame, and her medical degree at the University of Colorado School of Medicine. She completed her General Surgery Internship and Orthopaedic Surgery Residency at Case Western Reserve University in Cleveland, Ohio. Her fellowship training in Pediatric Orthopaedics was completed at the University of Utah. Dr. Hennessey is involved in clinical research and has several articles and book chapters to her credit. She is a board member on the University of Utah IRB, and is an active committee member in POSNA.