Brown graduated from Robinson Seminary in nearby Exeter in 1876. She then taught school for several years while contributing short stories to various magazines. Her success as a writer allowed her to give up teaching and move to Boston in 1884. She joined the staff of the Christian Register and in 1885 that of the Youth's Companion, with which she was associated for some years. Her first novel, Stratford-by-the-Sea, was published in 1884.

In 1895 Brown collaborated with her close friend Louise I. Guiney on Robert Louis Stevenson: A Study, and in 1896 she published By Oak and Thorn, a volume of travel impressions of England, and The Life of Mercy Otis Warren. Thereafter novels and collections of stories appeared at a rapid rate. She also wrote a volume of poems and several plays. Her dialect tales of New Hampshire folk gradually lost their appeal as popular interest in local-colour writing waned early in the century, and she never again attained the success of her work in that vein. In 1921 she published a biography of Guiney. She wrote nothing after 1935.