Elizabeth Lummis began writing verse as a child. She was educated at the Female Seminary in Aurora, New York. In 1834 her translation of Silvio Pellico (Pellico, Silvio)'s Euphemio of Messina was published anonymously, and the next year she published Poems, Translated and Original. Probably in 1835 she married William H. Ellet. Her Characters of Schiller (1839) was followed by Scenes in the Life of Joanna of Sicily and Rambles About the Country (both 1840) and by a number of poems and articles on literature for various leading magazines.

In 1848, after considerable research among authenticated and mainly primary sources, Ellet published Women of the American Revolution in two volumes, to which a third was added in 1850. The work (illustrated by Lilly M. Spencer (Spencer, Lilly Martin)) sketched the lives of some 160 women who had played a part in or commented on or merely observed the events of the Revolution; it long remained the major work in a neglected field and enjoyed several successful editions. From related materials she drew Domestic History of the American Revolution (1850). Her other books include Evenings at Woodlawn (1849), a collection of German legends; Pioneer Women of the West (1852), similar to her earlier work on the Revolution; and Women Artists in All Ages and Countries (1859).