Edith Louisa Sitwell was born in 1887 to Sir George Sitwell and his wife, Lady Ida Denison, daughter of Lord and Lady Londesborough. Edith spent most of her childhood at her parents’ home Renishaw Hall in Derbyshire. The first child and only daughter of an unhappy marriage, Edith never gained the respect and compassion that her brothers Osbert (born in 1892) and Sacheverell (born in 1897) experienced from Sir George and Lady Ida. She was educated at home and began writing poetry when she was about twenty, but the major change in her life came when she moved to London in 1914 to share a flat with Helen Rootham, her former governess.

Through her poetry, Sitwell challenged prevailing twentieth century British attitudes concerning literature and poetry. Sitwell's satiric poetry contradicted the bucolic, Georgian poetry of the day. In 1915, Sitwell published her first collection , although her role as editor of , an anthology of contemporary works published in 1916, gained her the most notoriety. She also used her poetic talents to oppose England's role in the first World War, and wrote politically dissident poetry at the end of World War II, specifically, from (1942), about bombing raids in London, and based on the bombing of Hiroshima.

Not only was Sitwell a talented political poet, but she was a talented performer as well. Allanah Harper, founder of , described Edith Sitwell during a performance writing she began to recite and a window opened onto an enchanted world. Each vowel and consonant flowed and she seemed to weave her poetry in the air. The world became heightened and transformed until I could see a whole landscape there behind her eyes. Sitwell's melodic voice coupled with highly syncopated lyrics lead to the success of her most famous work (1922). Intended to be performed, instead of silently read, the poems of focused on the sound and effect of chosen words instead of their meaning. The poems in (1929) capitalized on rhythm just as in , but they demonstrated a political seriousness absent from the previous work.

During the mid-1920s, Sitwell and her roommate Helen Rootham traveled frequently to Paris to visit Helen's sister Evelyn Weil. In Paris, Sitwell found a city filled with creativity and artistic talents, some of whom became influential friends, including Gertrude Stein. Sitwell enjoyed Gertrude's work and championed the modernist poet's 1926 Oxford and Cambridge lectures which effectively raised Gertrude's literary profile in Britain. It was in Gertrude's salon that Sitwell met the surrealist painter Pavel Tchelitchew, with whom she would enter perhaps her most important, yet often unfulfilling, relationship.

To Pavel Tchelitchew, a Russian émigré and artist, she was both a patron and muse. Unfortunately for Sitwell, Pavel's interest in her was purely intellectual, and possibly financial. The charming, passionate, and sometimes moody Pavel directed his amorous attention to the young American pianist, Allen Tanner, and eventually to Charles Henri Ford. Despite her difficulties with Pavel and her roommate Helen Rootham, whose ill-health and demanding nature caused much of Sitwell’s anxiety, Sitwell managed to compile (1933) and the controversial (1934).

Sitwell's relationships with other literary figures were much less hostile than her relationship with Pavel. She became patron to other authors, including Dylan Thomas, was close friends with poets H. D. (Hilda Doolittle) and Bryher, and became the goddaughter of Evelyn Waugh and Roy Campbell after her conversion to Catholicism in 1955.

In the 1930s Sitwell shifted her literary efforts from poetry toward prose after the success of her well-received historical biography (1930). Sitwell’s other historical biographies, (1936), (1946), and its sequel (1962), are some of her best known works of prose. (1937), her only published novel, came out the year her mother died.

During the early 1950s, Edith Sitwell received numerous honors. Four honorary doctorates from Leeds, Durham, Oxford, and Sheffield universities were bestowed upon her. In 1954, she was made Dame Commander of the British Empire in the Queen's birthday honors list.

Failing health and troubles with Osbert's lover David Horner forced Sitwell to move away from her childhood home in Renishaw and spend the final years of her life in a small flat and, later, a Queen Anne style cottage she called in Hempstead. During her later years, with the help of her personal assistant Elizabeth Salter, Edith published her final volume of poetry (1962) and the sequel to , (1962). Sitwell died in 1964 and her autobiography was published posthumously in 1965.