In 1797, ten-year-old Mary won her father a lottery ticket worth £20,000, but by the 1810s the small family suffered financial difficulties.

Her father engaged Frances Arabella Rowden, formerly governess to the family of Frederick Ponsonby, 3rd Earl of Bessborough, to give her extra tuition.

Mitford's youthful ambition had been to be the greatest English poetess, and her first publications were poems in the manner of Samuel Taylor Coleridge and Walter Scott (Miscellaneous Verses, 1810, reviewed by Scott in the Quarterly; Christina, the Maid of the South Seas, a metrical tale based on the first news of discovery of the last surviving mutineer of the H. M. S. Bounty and a generation of British-Tahitian children on Pitcairn Island in 1811; and Blanche, part of a projected series of "Narrative Poems on the Female Character", in 1813).

Her talk was said by her friends, Elizabeth Barrett Browning and Hengist Horne, to have been even more amusing than her books, and five volumes of her Life and Letters, published in 1870 and 1872, show her to have been a delightful letter-writer.

Both rise to heights rarely found either in the women's journalism of her day or in a woman who by every law of the time should have been crushed by adversity.

"[3] On the other hand, Tom Fort, writing in 2017, took the view that "for a reader of today she is rather hard going ... She is, I'm sorry to say, trite, sentimental, long-winded, short-sighted, arch, chatty and twee.

The strain of poverty told on Mitford's work, for although her books sold at high prices, her income did not keep pace with her father's extravagances.