See B. P. Broadhurst, Social Thought, Social Practice, and Social Work Education (1971).
Sanborn was born at Hampton Falls, New Hampshire, the son of Aaron and Lydia (Leavitt) Sanborn. He graduated Harvard in 1855. As secretary of the Massachusetts Kansas Commission he came into close touch with John Brown.
He was one of the founders of, and was closely identified with, the American Social Science Association, the National Prison Association, the National Conference of Charities, the Clarke School for the Deaf, the Massachusetts Infant Asylum, and the Concord School of Philosophy.
From 1874 to 1876 he was chairman of the Massachusetts State Board of Charities, and from 1879 to 1888 State Inspector of Charities. He lectured at Cornell, Smith, and Wellesley, edited writings of Thoreau, Paul Jones, J. H. Payne, Mary Shelley, and Thomas Love Peacock, and also published a number of books. He lived at Concord, Massachusetts.