Letitia Elizabeth Landon was born on 14 August 1802 in Chelsea, London to John Landon and Catherine Jane, née Bishop. A precocious child, Landon learned to read as a toddler; an invalid neighbor would scatter letter tiles on the floor and reward young Letitia for reading, and, according to her father, "she used to bring home many rewards." At the age of five, Landon began attending Mrs Rowden's school at 22 Hans Place, which counted among its alumnae Mary Russell Mitford and Lady Caroline Lamb. The family moved to the country in 1809, so that John Landon could carry out a model farm project, and Landon was educated at home by her cousin Elizabeth from that point on. Elizabeth, though older, soon found her knowledge and abilities outstripped by those of her pupil: "When I asked Letitia any question relating either to history, geography, grammar - Plutarch's Lives, or to any book we had been reading, I was pretty certain her answers would be perfectly correct; still, not exactly recollecting, and unwilling she should find out just then that I was less learned than herself, I used thus to question her: 'Are you quite certain?' ... I never knew her to be wrong."

An agricultural depression soon followed, and the family moved back to London in 1815, where John Landon made the acquaintance of William Jerdan, editor of the Literary Gazette. According to 19th-century commentator A. Thomson, Jerdan took notice of the young Landon when he saw her coming down the street, "trundling a hoop with one hand, and holding in the other a book of poems, of which she was catching a glimpse between the agitating course of her evolutions." Jerdan encouraged Landon's poetic endeavors, and her first poem was published under the single initial "L" in the Gazette in 1820, when Landon was 18. The following year, with financial support from her grandmother, Landon published a book of poetry, The Fate of Adelaide, under her full name. The book met with little critical notice but sold well; Landon, however, never received any profits, as the publisher went out of business shortly thereafter. The same month that The Fate of Adelaide appeared, Landon published two poems under the initials "L.E.L." in Gazette; these poems, and the initials under which they were published, attracted much discussion and speculation. As contemporary critic Laman Blanchard put it, the initials L.E.L. "speedily became a signature of magical interest and curiousity." Bulwer Lytton wrote that, as a young college student, he and his classmates would

rush every Saturday afternoon for the 'Literary Gazette,' [with] an impatient anxiety to hasten at once to that corner of the sheet which contained the three magical letters L.E.L. And all of us praised the verse, and all of us guessed at the author. We soon learned it was a female, and our admiration was doubled, and our conjectures tripled."

Landon served as the Gazette's chief reviewer as she continued to write poetry; her second collection, The Improvisatrice, appeared in 1824.

Landon's father died later that year, and Landon was forced to use her writing to support both herself and her family; contemporaries saw this profit-motive as detrimental to the quality of Landon's work.

By 1826, Landon's high reputation began to suffer as rumors began to appear in the gutter press that she had had affairs or secretly borne children. Landon continued, however, to publish poetry, and in 1831 she published her first novel, Romance and Reality. She became engaged to John Forster. Forster became aware of the rumours regarding Landon's sexual activity, and asked her to refute them. Landon responded that Forster should "make every inquiry in [his] power," which Forster did; after he pronounced himself satisfied of Landon's purity, however, Landon broke off their engagement. To him, she wrote:

The more I think, the more I feel I ought not - I can not - allow you to unite yourself with one accused of - I can not write it. The mere suspicion is dreadful as death. Were it stated as a fact, that might be disproved. Were it a difficulty of any other kind, I might say, Look back at every action of my life, ask every friend I have. But what answer can I give ... ? I feel that to give up all idea of a near and dear connection is as much my duty to myself as to you....

Privately, however, Landon stated that she would never marry a man who had mistrusted her. In a letter to Bulwer Lytton, she wrote that "if his future protection is to harass and humiliate me as much as his present - God keep me from it ... I cannot get over the entire want of delicacy to me which could repeat such slander to myself."

After this, Landon began to "[talk] of marrying any one, and of wishing to get away, from England, and from those who had thus misunderstood her." In October 1836, Landon met George Maclean, governor of the Gold Coast (now Ghana), at a dinner party, and the two began a relationship. Maclean, however, moved to Scotland early the following year, to the surprise and distress of Landon and her friends. After much prodding, Maclean returned to England and he and Landon were married shortly thereafter, on 7 June 1838. The marriage was kept secret, and Landon spent the first month of it living with friends. In early July, the couple sailed for Cape Coast, where they arrived on 16 August. Two months later, on 15 October, Landon was found dead, a bottle of prussic acid in her hand.

Among the poets of her time to recognise and admire her were Elizabeth Barrett Browning, who wrote "L.E.L.'s Last Question" in homage, and Christina Rossetti, who published a tribute poem entitled "L.E.L" in her 1866 volume "The Prince's Progress and Other Poems."

Her reputation, while high in the 19th century, fell during most of the 20th as literary fashions changed. and Landon's poetry was perceived as overly simple and sentimental. In recent years, however, scholars and critics have increasingly studied her work, beginning with Germaine Greer in the 1970s. Critics such as Isobel Armstrong argue that the seeming simplicity of poetry such as Landon's is deceptive, and that women poets of the 19th century often employed a method of writing which allows for multiple, concurrent levels of meaning.