Dr. Andrews was born in North Haven, Connecticut, and received his B.A. (1855) and M.A. (1858) degrees from Yale University. In 1861, he enlisted in the Civil War, taking part in many engagements with the enemy, but ill health led him to resign his commission in 1862. He studied medicine at Yale, graduating in 1863, and again entered the Union Army as a surgeon until the war ended.
In 1862, Dr. Andrews became an assistant physician at the Utica (N.Y.) State Lunatic Asylum and served there until 1880, when he was appointed superintendent of the New Buffalo State Hospital, a position he held until his death. He also served as a professor of medicine at Buffalo Medical College.
Dr. Andrews was active in medical organizations, founder of the New York Medical Association and its president in 1892. He served as President of the Section of Psychological Medicine & Nervous Diseases of the 9th International Congress held in Washington, D.C., in 1887. He was a frequent contributor of papers to medical societies and journals, and for ten years, he served as an associate editor of the American Journal of Insanity. Noteworthy were his successful efforts to train nurses and aides to care for the insane. Dr. Andrews was President of the American Medico-Psychological Association (1892–93).