Franklin was born in Bicester, Oxfordshire, England, one of six children of Charles Franklin, an upholsterer and cabinetmaker, and Mary Clifton, after whom she was christened 'Mary'. She may have posed for Whistler as early as 1872, as a stand-in for his portrait of Mrs. Frances Leyland, when she was fifteen.
By the late 1870s she was serving as a model to Whistler for etchings and painted portraits, most notably the Arrangement in White and Black. She also was the initial model for what would be the Portrait of Miss Florence Leyland, as well as Harmony in Grey and Peach Colour, numerous other oils, drawings, watercolors, etchings, and lithographs.
Franklin had two daughters by Whistler: Ione (born circa 1877) and Maud McNeill Whistler Franklin (born 1879). She sometimes referred to herself as 'Mrs. Whistler', and in the census of 1881 gave her name as 'Mary M. Whistler'.
She was not always well treated by Whistler; at the time of his libel trial with John Ruskin in January 1879 he left Franklin, then pregnant, in a London hotel under the pretense that he was in Paris. Following Whistler's bankruptcy later that year she accompanied him to Venice, but was not accepted into society. In the 1880s her health suffered, and she was the subject of watercolors by Whistler depicting her in bed.
After Whistler married Beatrice Godwin in 1888, Franklin moved to Paris. She married a New York man named John A. Little; in 1904 he died, and around 1911 Franklin married another American, Richard H.S. Abbott, and lived near Cannes until her death.
- Spencer, Robin, Whistler. Studio Editions Ltd., London, 1993.
- The Correspondence of James McNeill Whistler, University of Glasgow