Born in Stockbridge, Massachusetts, she was the daughter of a prosperous lawyer and successful politician who later became a judge of the Massachusetts supreme court. She was sent to study at a finishing school in Boston and as a young lady, 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.
In 1827, her third novel Hope Leslie recounted a dramatic conflict between British colonists and Native Americans. The book achieved a large readership and made her one of the most talked about female novelists of the day. Catharine Sedgwick's writings involved American settings, combining patriotism with protestations against Puritan oppressiveness. Her topics would become important to the creation of a national literature enhanced through her detailed descriptions of nature. Although moralistic, Sedgwick created spirited heroines who, as the focal point of her stories, did not conform to the stereotypical conduct of women at the time. In her later work, Married or Single , she put forth the bold idea that women should not marry if it meant they would lose their self-respect.
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 passing in 1867, by the end of the 19th century she had been relegated to near obscurity status. Interest in her works and an appreciation of her contribution to American literature has been recognized through the advent of low-cost electronic reproductions available at the end of the 20th century.
Sedgwick's first novel, A New-England Tale was published in 1822, and she is numbered among a group of nineteenth-century writers who helped found a uniquely American body of literature.
Sedgwick wrote both fiction and nonfiction and there is a didactic tone in all her work that stresses the need for religious and racial tolerance, as well as social and political reform.
Sedgwick's works were considered innovative during her own time because she was one of the first American writers to use local scenery, customs, and characters.