Zimmern and her parents emigrated to Britain in 1850, and she was naturalized upon coming of age. Her first appearance in print was a story for Once a Week, and she was soon writing for the Argosy and other magazines. A series of children's stories, first published 1869-71 in Good Words for the Young, were reprinted as Stories in Precious Stones (1873) and followed by another collection, Told by the Waves. A series of tales from the Edda appeared in Old Merry's Monthly in 1872, before being similarly republished.

In 1873 Zimmern began writing critical articles, particularly on German literature, for the Examiner. She would also write for Fraser's Magazine, Blackwood's Magazine, the Athenaeum, the Spectator, St James's, Pall Mall Magazine, the World of Art, the Italian Rassegna Settimalane and various German papers. Through her advocacy and translations, Zimmern made European culture - whether that of Germany, or, increasingly, Italy - accessible to English speakers. She lectured on Italian art in Britain and Germany, and translated Italian drama, fiction and history. 'Jewish Home Life,' an 1881 Fraser's contribution, criticized Germans for their anti-semitism and urged Jewish assimilation. She befriended Friedrich Nietzsche, two of whose books she would later translate, in Switzerland in the mid-1880s. By the end of the decade had settled in Florence, where she was associated with the Corriere della Sera and also edited the Florence Gazette. In later life she defended Italian values against what she saw as the threat of German expansionism.

Books

• The Hansa Towns, 1891
• Arthur Schopenhauer, his Life and his Philosophy, 1876
• Gotthold Ephraim Lessing, his Life and his Works, 1878
• (ed.) The Discourses of Joshua Reynolds
• Tales from the Edda
• The Italy of the Italians, 1906
• The New Italy, 1918

Translations

• Half-Hours with Foreign Novelists, 1880. (Sections of various novels, with her sister Alice Zimmern)
• Nietzsche, Beyond Good and Evil, 1906
• Nietzsche, Human, All Too Human, 1909
• Ferdowsi, Shahnameh (The Epic of Kings), 1883, Iran Chamber Society, MIT.