Graduating from high school in Montana, Dr. Houlihan spent 4 years as a member of an elite special operations unit, the 2nd Ranger Battalion. Upon completion of his service agreement Dr. Houlihan returned to the University of Montana where he received his Bachelor's of Science. He then went on to receive his dental degree (D.M.D.) at Oregon Health Sciences University in Portland. His next four years were spent practicing dentistry in the Army Dental Corps. where he served two tours in Operation Iraqi Freedom treating the dental needs of U.S. and coalition troops and contractors before returning to Oregon to pursue his dreams of private practice.