Aiken was the eldest son of William Ford and Anna (Potter) Aiken. In Savannah, Aiken's father became a respected physician and eye surgeon, while his mother was the daughter of a prominent Massachusetts Unitarian minister. On February 27, 1901, Dr. Aiken murdered his wife and then committed suicide. According to his autobiography, Ushant, Aiken, then 11 years old, heard the two gunshots and discovered the bodies immediately thereafter. After his parents' deaths, he was raised by his great-aunt and uncle in Cambridge, Massachusetts, attending Middlesex School then Harvard University.