Born in New York City, the daughter of Michael and Melanie (Fisher) Deutsch, she matriculated from the Ethical Culture School and Barnard College, graduating in 1917 with a B.A. She published poems in magazines such as the North American Review and the New Republic while she was still a student at Barnard.
In 1946, she received an honorary D. Litt. from Columbia University. On April 29, 1921, Deutsch married Avrahm Yarmolinsky, chief of the Slavonic Division of The New York Public Library (1918–1955), also a writer and translator. They had two sons, Adam Yarmolinsky and Michael.
She translated Pushkin'sEugene Onegin into English and also made some of the best English versions of Boris Pasternak's poems.