Early adulthood

Inspired by his Uncle Henry's worldwide adventures in the U.S. Navy, Gardner decided to enlist when he finished secondary schooling. He was stationed at Camp Lejeune in North Carolina for four years, where he was assigned as a hospital corpsman. He became acquainted with a decorated San Francisco cardiac surgeon, Dr. Robert Ellis, who offered Gardner a position assisting him with innovative clinical research at the University of California Medical Center and Veterans Administration Hospital in San Francisco. Gardner accepted the position and moved to San Francisco upon his discharge from the Navy in 1974. Over the course of two years, he learned how to manage a laboratory and to perform various surgical techniques. By 1976, he had been given full responsibility for a laboratory and had co-authored several articles with Dr. Ellis that were published in medical journals.