Dr. Ruggles was born in Hanover, New Hampshire, and graduated from Dartmouth College (1902) and Harvard Medical School (1906). He spent summers at Danvers State Hospital, where his interest in psychiatry became evident. He accepted a position at Butler Mental Hospital in Rhode Island in 1907 and remained there until 1909.
Dr. Ruggles served in the U.S. Army during WWI, directing a base hospital in France. He returned to Butler after the war and became superintendent in 1922. In 1925, he was invited to establish a Department of Mental Hygiene at Yale University during a leave of absence from Butler. He remained at Butler for many years.
During his career, Dr. Ruggles was active as a teacher at Yale, Brown, and Dartmouth Universities. He was President of the National Committee for Mental Hygiene (1934–40), Secretary (1938–41) of the American Psychiatric Association, and then President (1942–43).