Born in Stockbridge, Massachusetts, she was the daughter of a prosperous lawyer and successful politician, Theodore Sedgwick, who later became a judge of the Massachusetts Supreme Judicial Court and Speaker of the United States House of Representatives. She was sent to study at a finishing school in Boston, and as a young woman she took charge of a school in Lenox. Sedgwick's conversion from Calvinism to Unitarianism led her to write a pamphlet denouncing religious intolerance that evolved into her first novel,
A New-England Tale.
Much in demand, from the 1820s to the 1850s Catharine Sedgwick made a good living writing short stories for a variety of periodicals. Following her death in 1867, by the end of the 19th century she had been relegated to near obscurity. Interest in her works and an appreciation of her contribution to American literature was largely stimulated by the advent of low-cost electronic reproductions that became available at the end of the 20th century.
Edgar Allan Poe gave a description of her in his
The Literati of New York CityShe is about the medium height, perhaps a little below it. Her forehead is an unusually fine one nose of a slightly Roman curve; eyes dark and piercing; mouth well-formed and remarkably pleasant in its expression. The portrait in “Graham's Magazine” is by no means a likeness, and, although the hair is represented as curled, (Miss Sedgwick at present wears a cap...at least, most usually,) gives her the air of being much older than she is.
She is buried in the family plot in Stockbridge, Massachusetts.