She exhibited literary talent at an early age and in 1787 published her first novel, The History of Lady Emma Melcombe, and Her Family. Aged 23, she married Joseph Gales, Sr., a liberal reform supporter and abolitionist. Because of his views, he eventually fled England for continental Europe, leaving Winifred in charge of the family bookstore and printing press. With the political climate in England and a warrant for his arrest precluding her husband's return, Winifred Gales sold the Sheffield Register newspaper to its assistant editor, James Montgomery, and joined her husband in Altona near Hamburg, Germany.
In 1795, the Gales family sailed to Philadelphia and four years later settled in Raleigh, North Carolina where Joseph Gales became editor and printer of The Raleigh Register, a newspaper supporting Jeffersonian Republicanism. In 1804, Gales published Matilda Berkely; or, Family Anecdotes, which is considered the first novel ever published in North Carolina by a resident of that state. Firm Unitarians and promoters of tolerance, the Gales left Raleigh for Washington, D.C. in 1833 amid growing orthodox trends in North Carolina. She died in Washington in 1833, and is buried in the Congressional Cemetery.
- Elliot, R. B. (1986). Gales, Winifred Marshall. In Dictionary of North Carolina Biography (Vol. 2, pp. 270). Chapel Hill: University of North Carolina Press.
- Eaton, Clement. 1944. Winifred and Joseph Gales: Liberals in the Old South. Journal of Southern History 10:4, 461-74
-  Gales, Winifred and Joseph Gales. Gales Family Papers. Southern Historical Collection, Louis Round Wilson Library, University of North Carolina at Chapel Hill.
-  Gales, Winifred. Congressional Cemetery entry