Iseult Gonne was the daughter of the Irish nationalist, Maud Gonne. As an illegitimate daughter who lived in France, it was not until the divorce case between Maud Gonne and John MacBride took place in 1905-6 that her existence became known to the wider public. W. B. Yeats, Maud Gonne's lifelong admirer, knew of Iseult's existence from 1898 and became a close part of her life. Yeats proposed to Maud Gonne in July 1916 and then Iseult soon after. He was rejected by both. Maud and Iseult Gonne were both the subjects of a number of poems written by Yeats.

In 1913, Iseult met Rabindranath Tagore. Inspired by his poetry, she began to learn Bengali in 1914. She was tutored by Devabrata Mukerjea, with whom she also had an affair. Together, in France, they translated some of Tagore's The Gardener into French directly from the Bengali. Tagore left it to Yeats' discretion to decide the merit of the work, but Yeats did not feel sufficiently bilingual in French to judge them. The translations were never published. Iseult attracted a number of other men, including Ezra Pound. In 1920, she married Francis Stuart, a poet of Ulster descent. When Maud Gonne died in 1953, Iseult was not acknowledged as her mother's daughter in her will. Iseult died a year later.