Madame Sarah Grand was born Frances Elizabeth Bellenden Clarke in Rosebank House, Donaghadee, County Down, Ireland of English parents. Her father was Edward John Bellenden Clarke (1813–1862) and her mother was Margaret Bell Sherwood (1813–1874). When her father died, her mother took her and her siblings back to Bridlington, England to be near her family who lived at Rysome Garth near Holmpton in East Yorkshire.
In 1868 Frances was sent to the Royal Naval School, Twickenham, but after a year she was asked to leave and went on to a finishing school in Kensington, London. In August 1870, at the age of sixteen, she married (some say eloped with) widowed Army surgeon David Chambers McFall, who was 21 years her senior and had two sons from his previous marriage: Chambers Haldane Cooke McFall and Albert William Crawford McFall. Frances and Chambers McFall's only child, David Archibald Edward "Archie" McFall, was born in Sandgate, Kent, on 7 October 1871. (Her son became an actor and took the name Archie Carlow Grand.) From 1873 to 1878 the family travelled in the Far East. In 1879 they moved to Norwich, and in 1881 to Warrington, Lancashire where her husband retired.
The marriage was not a happy one, and in 1890 Frances left her husband to pursue her writing career and changed her name to Madame Sarah Grand. She lived in London for a while and then for 20 years in Tunbridge Wells, Kent, during which time she took an active part in the local women's suffrage societies, as well as travelling extensively, particularly to the United States. In 1920 she moved to Bath and was for several years Lady Mayoress alongside Mayor Cedric Chivers. She died at her home at The Grange in Calne, Wiltshire, on 12 May 1943.
Her work dealt with the New Woman in fiction and in fact, she wrote treatises on the subject of the failure of marriage, and her novels may be considered strongly anti-marriage polemics.
The New Woman novel was a development of the late 19th century. New Woman novelists and characters encouraged and supported many different types of political action in Britain. For some women, the New Woman movement provided support for women who wanted to work and learn for themselves, and who started to question the idea of marriage and the inequality of women. For other women, especially Sarah Grand, the New Woman movement allowed women to speak out not only about the inequality of women, but about middle-class women's responsibilities to the nation. In The Heavenly Twins Grand demonstrates the dangers of the moral double standard which overlooked men's promiscuity while punishing women for the same acts. More importantly, however, Grand argues in The Heavenly Twins that in order for the British nation to grow stronger, middle-class women have the responsibility of choosing mates with whom they might produce strong, well-educated children.