Dr. Larkin graduated from medical school with Honors from the State University of New York, Upstate Medical Center in Syracuse. After that he had his internship, residency and fellowship training in anesthesiology and pain management at Walter Reed Army Medical Center. After finishing his residency training he stayed on as staff at Walter Reed for another 7 years. During this period he served at various times as the chief of the pain management clinic as well as the chief of the anesthesia department.

During this tenure at Walter Reed the pain service grew from an afterthought to a nationally known and respected institution in the field of pain management which has been featured in national magazines and profiled on television. He left the Army as a Lieutenant Colonel to pursue a career in private practice.