Dr. Sheerin was born and raised in New York City. His first experience with horses was soon after his family moved to Lagrangeville, a small town north of the city. He began working on a thoroughbred breeding farm where he gained experience in all aspects of the thoroughbred industry. During high school, he also competed on the varsity crew team. His love of rowing took him to Syracuse University, where he majored in biology.

Following graduation, Dr. Sheerin moved to Florida to manage a small thoroughbred breeding farm in Ocala. Several years later, he began graduate research in equine reproductive physiology at the University of Florida under mentor Dr. Dan Sharp while managing the endocrinology lab at the University of Florida College of Veterinary Medicine.

While in veterinary school, Dr. Sheerin expanded his interest in theriogenology, particularly large animal theriogenology. After graduating from the University of Florida College of Veterinary Medicine in 1994, Dr. Sheerin joined a mixed practice in Live Oak, FL before moving to New Freedom, PA to join Nandi Veterinary Associates. Dr. Hurtgen’s knowledge and teaching encouraged Dr. Sheerin to return to the University of Florida for a theriogenology residency. Dr. Sheerin became board certified in 2001, and upon completion of his residency, Dr. Sheerin and his family returned to New Freedom. The following year, the Sheerins moved to Lexington, KY to join Rood & Riddle Equine Hospital, where Dr. Sheerin joined one of his veterinary school mentors, Dr. Michelle LeBlanc, as a staff theriogenologist. The Sheerin’s returned to Nandi in 2011 to continue Dr. Hurtgen’s legacy. In October 2021, Dr. Sheerin returned to Rood & Riddle Equine Hospital after closing his practice in Pennsylvania.

He is a member of the American Association of Equine Practitioners, the American Veterinary Medical Association and the Society for Theriogenology. Dr. Sheerin has lectured nationally and internationally on the reproductive aspects of the mare and stallion. Dr. Sheerin and his wife, Barb, have three daughters, Mary, Anne and Sarah, who are all involved in the equine industry in various capacities. Barb breeds and shows Welsh ponies with a little help from Dr. Sheerin.