John Mersch, MD

"Parenting is 'on the job training' and you've been hired! A good pediatrician should serve as a knowledgeable resource of practical information and medical expertise. My enjoyment of pediatrics springs from the nature of this special area of medicine - the science of the human biology coupled with emotional support for parents and their children as they both grow and mature. My personal interests include pediatric sports medicine and developmental pediatrics. As a father of three, I am aware of both the common and extraordinary challenges parents accept. I look forward to providing a ready resource for you and your family."

On staff at Saddleback Memorial Medical Center, Mission Hospital and Children’s Hospital of Orange County (CHOC) at Mission, Dr. Mersch serves on the Medical Executive Committee at Mission Hospital.

A resident of San Juan Capistrano, Dr. Mersch has three children- Kimberly is married, completed medical school and is following in her father’s footsteps as a Resident in Pediatrics, Caroline is working toward her high school teaching credential in art, and John is a physics major and will pursue postgraduate studies in alternative energy.  After being widowed in 2000, Dr. Mersch has since remarried.  He and his bride Joanne are now celebrating their new life together.

When he is not taking care of his patients, Dr. Mersch enjoys competing in triathlons, skiing and listening to music. He is also active with the Boy Scouts of America.

Dr. Mersch says that even though the bureaucracy of pediatrics has changed remarkably since starting with SOCPA in 1982 (insurance forms, authorization requirements, etc.), it is still fun to go into an exam room and interact with the patient and his/her parents. Dr. Mersch has a special interest in sports medicine.

This physician is a member of MemorialCare Physician Society which drives clinical outcomes and performance for MemorialCare Health System.


  • Pediatrics


Medical Education
University of Southern California - Keck School of Medicine
Date Completed:
Children's Hospital Los Angeles

MemorialCare Hospital Affiliations