Mary Barber was born in Ireland and became a friend and protégée of Jonathan Swift. She married Rupert Barber, a Dublin woollen draper and amateur artist whose pastel drawing of Swift hangs in the National Portrait Gallery in London. She and her husband had nine children, four of whom lived to adulthood. For many years, she wrote poetry only for family consumption, until Swift made her well-known by including her as a member of his "triumfeminate," along with Constantia Grierson and Elizabeth Sican. She became part of his circle and got to know Laetitia Pilkington, Mary Delany, Thomas Tickell, and Elizabeth Rowe. Swift's patronage was a substantial factor in the success of her collection Poems on Several Occasions (1734). Her health declined and she subsequently published little beyond a few poems in the Gentleman's Magazine in 1737. She died in or around 1755. That year saw her work included in the book Poems by Eminent Ladies, along with that of Aphra Behn and Lady Mary Wortley Montagu.