She was two years old when her mother died and her father sent her away to live with her maternal grandfather, who was a linen draper in Framlingham, Suffolk.
Alethea became engaged to William Springal Levett, son of an Aldeburgh physician and a friend of the poet George Crabbe, but he died in 1774 before they could marry.
The couple lived in Philadelphia for a year, then returned to England and settled finally in Penkridge, Staffordshire, where she died in 1827.
Some of the more uncertain works (Things by their Right Names, 1812, Rhoda, 1816, and Isabella, 1823) have also been attributed to Frances Jacson.
Some (Essays on the Art of being Happy, 1803, A Tale without a Title: Give it what you Please, 1804, The Nuns of the Desert, or, The Woodland Witches, 1805, and the four-volume The Discarded Daughter, 1810) were published under the pseudonym Eugenia de Acton.