Dr. Kilbourne was born in Keokuk, Iowa. He graduated from the medical department of the University of the City of New York in 1883, and at once served his apprenticeship in state hospital work under an excellent tutor, Dr. A. E. MacDonald. The following year, he obtained a position on the staff of St. Peter State Hospital in Minnesota. After four years as an assistant physician at St. Peter, Dr. Kilbourne was appointed superintendent of the Rochester State Hospital on June 6, 1889. He held that position of superintendent for 45 years and died on November 30, 1934, while still occupying that position.
His interests were not confined to state hospital work alone; at the time of his death, he was past President of the Olmstead County Medical Society and was a member of all leading local, state, and national medical associations. In his own city, he was a member of the Library Board for 25 years; he was a senior warden in the Calvary Episcopal Church; he was active in Masonic circles; and for many years, he was a member of the Rotary Club.
Dr. Kilbourne became a member of the American Medico-Psychological Association in 1890, took an active part in its work, and attended all of its meetings without fail. Dr. Kilbourne was President of the American Medico-Psychological Association (1908–09).