Dr. Mark Johnson graduated from Indiana University School of Dentistry in 1975. He served two years active duty in the U.S Navy Dental Corps. Following discharge, Dr. Johnson was in private practice in Marion, Indiana.
Dr. Johnson was Assistant Chief, Dental Service at the Veterans Administration hospital in Marion, Indiana, and Chief of Dental Services in the Jacksonville, Florida, and Daytona Beach, Florida VA Outpatient Clinics.
He is retired from the U.S. Army Dental Corp after thirty years of reserve service. Dr. Johnson was also assistant professor of clinical operative dentistry at Indiana University School of Dentistry and clinical undergraduate periodontics at University of Florida School of Dentistry.
While in Marion, Indiana, Dr. Johnson served for ten years with the American Red Cross as a member of the Board of Directors and as Disaster Chairman, as a member of the Budget and Allocations committee of United Way, and as Deputy Coroner of Grant County, Indiana.