Dr. Johnson, who is a South Dakota native, founded the Brookings Dental Clinic in 1978, following his graduation from the University of Nebraska Medical Center, College of Dentistry. During his years in practice, Dr. Johnson has been a member of the American Dental Association and South Dakota Dental Association. He has served multiple times as a delegate to the SDDA and is a past president of the Northern District Dental Association. Dr. Johnson spent six years on the SD State Board of Dentistry and was an examiner for the Central Region Dental Testing Service. He was honored by Governor Dennis Daugaard with “Dr. Geoffrey Johnson Day” in 2011, and he is a senior member of the Siouxland Study Club. Dr. Johnson and his wife, Elizabeth, have three grown children and eight grandchildren.