Born in Texas, Harris took his science degree in 1938 from the University of Arkansas Medical School. In 1942 he began his psychiatry training in Washington DC at St. Elizabeth Hospital. He was a Navy psychiatrist for several years, becoming chief of the Psychiatry Branch and leaving the service as a commander. This was followed by a teaching post back at the University of Arkansas, and then a period as a senior mental health bureaucrat. He continues to practice psychiatry in Sacramento, California, and is a director of the Transactional Analysis Association.