H.D. was born and spent her early years in Bethlehem, Pennsylvania. Her father was a professor of astronomy and mathematics at Lehigh University. Her mother belonged to the Moravian brotherhood, a protestant sect that argued for a direct, sensuous perception of God, a belief that finds parallel expression in H.D.'s early imagist poetry. Hilda enrolled at Bryn Mawr College but found herself deeply conflicted. She had met and become engaged to poet Ezra Pound but was simultaneously attracted to a girlfriend, Frances Gregg. Soon the women were on a boat to Europe, where Hilda became involved with Pound again; though the relationship faltered, Pound did come up with the name "H.D.," which she would continue to use. Although she visited the United States, her home thereafter would be abroad.

Doolittle met and married poet-translator Richard Aldington, published her first book of poetry, Sea Garden (1916), and soon the couple met and became intimately involved with D.H. and Frieda Lawrence. In the midst of the wartime chaos, H.D. also met the wealthy writer Winifred Ellerman ("Bryher"), who had committed the entirety of Sea Garden to memory; they would be lifelong friends. From time to time, H.D. was beset by anxiety, and she even travelled to Vienna to be analyzed by Freud in the 1930s, but through it all she remained productive, writing poetry and fiction and doing translation from the Greek. During World War II, she would write a major long poem, Trilogy (1944-1946), and follow it with another, Helen in Egypt (1961), but she has remained most well known for the riveting power of the poems that simultaneously defined the imagist movement and exceeded what most other writers could do under its banner. H.D. calls up forces out of nature, intensifies them, and enlists them in vatic psychological demands. At moments in these poems, a transgressive otherness breaks through subjective identity. Myth and nature are placed in dynamic, transformative relationships with a poem's speaker. No readers who open themselves to her work can ever think of imagism as merely pictorial.