Upon graduation from Miami High School John Nidiffer attended OSU for one year and then was drafted into the US Army where he served for 6 years. He served two tours in Vietnam, one as an artillery officer and one as a Cobra Helicopter pilot. While in the Army he received two Distinguished Flying Crosses, 16 Air Medals, and two Bronze Stars. He left the Army in 1972 as a Captain and entered the University of Oklahoma College of Pharmacy. John graduated from with a Bachelor of Science in Pharmacy in 1975 and a Master of Public Health in 1993. In 1996 he became a Certified Public Health Pharmacist, Royal Society of Health, U.S. Branch.

John has been married for 36 years to wife, Rita and they have three daughters: Angie, a teacher, Amy, a teacher, and Amber, a physical therapy student at The University of Oklahoma Health Sciences Center. They also have 5 granddaughters and are expecting their first grandson the middle of April.

John has worked as both a retail pharmacist and hospital pharmacist for the first 14 years of his professional career and in 1989 he entered the U.S. Public Health Service. He is currently Chief Pharmacist at the Wewoka Indian Health Center in Wewoka, Oklahoma.