Althrough Cunard lived the life of a wealthy young socialite, travelling and mingling with the literary elite, the 1920s also saw her working seriously at establishing herself as a poet. Parallax was published by Leonard and Virginia Woolf’s Hogarth Press in 1925; the poem powerfully capturing the pessimism of the modernist sensibility. It centres on the wanderings of a young male poet through London, Paris, and Italy as he contemplates love, friendship, and art.
The harsh critical reception of her work indicated some of the struggles faced by women poets in establishing themselves in the male-dominated high Modernist literary sphere. Her style was considered romantic and old-fashioned by the arch-Modernist Ezra Pound. Meanwhile, T.S. Eliot mocked her poetic aspirations in an excised section of the Waste Land. For her part, Cunard admired Eliot’s work, and Parallax is indebted to the Waste Land. The poet Samuel Beckett was a great admirer of the poem and Cunard’s friend, Irene Rathbone, described it as “young and bitter and life-loving and crazy and joyous and sad".
She moved to Paris in the 1920's, where she became involved with literary Modernism, Surrealists and Dada. In 1928 she set up the Hours Press. Cunard wanted to support experimental poetry and provide a higher-paying market for young writers; her inherited wealth allowed her to take financial risks that other publishers could not. Hours Press became known for its beautiful book designs and high-quality production. It brought out the first separately published work of Samuel Beckett, and also Ezra Pound's Draft of XXX Cantos. Cunard published old friends like George Moore, Norman Douglas, Roy Campbell, Harold Acton, Brian Howard, and Robert Carlton Brown.
In 1928 she began a relationship with Henry Crowder, an African-American jazz musician. She became an activist in matters concerning racial politics and civil rights in the USA. In 1934 she edited the massive Negro Anthology, collecting poetry, fiction, and non-fiction primarily by African-American writers. In the mid-1930s she took up the anti-fascist fight as well, writing about Mussolini's annexation of Ethiopia and the Spanish Civil War. During World War II, Cunard worked, to the point of physical exhaustion, as a translator in London on behalf of the French Resistance.
In later years, Cunard suffered from mental illness and poor health, worsened by alcoholism, poverty, and self-destructive behaviour. She was committed to a mental hospital after a fight with London police; but, after her release, her health declined even further. In 1965, she was found penniless on the streets, her weight having dropped to 60 pounds. She was taken to the Hôpital Cochin in Paris where she died two days later.