Marguerite Young was born in Indianapolis, Indiana, and began writing at an early age. Her parents separated when she was very young, and she and her sister were brought up by their maternal grandmother. She received a bachelor's degree in French and English at Butler University in Indianapolis, and earned a master's in Elizabethan and Jacobean Literature at the University of Chicago.
She taught English in Indianapolis and at the University of Iowa, and published her first collection of poetry, Prismatic Ground, in 1939. That same year, she made her first visit to the commune of New Harmony, Indiana, where her mother and stepfather lived, later moving there herself. In 1945, she published Moderate Fable, which won the poetry prize from the National Academy of Arts and Letters, and Angel in the Forest. During the next 50 years, she became a well-known figure in New York's Greenwich Village, moving in literary circles that included Richard Wright, Anaïs Nin, Flannery O'Connor, Allan Tate, Carson McCullers, and Truman Capote. She wrote articles, poetry, and book reviews while also teaching creative writing at the New School for Social Research and Fordham University, among others.
Her epic novel Miss MacIntosh, My Darling (1965), written over the course of 18 years, developed a cult following. In the late 1960s, she put aside a book she was writing on James Whitcomb Riley to produce a biography of her friend Eugene V. Debs, which was to occupy the rest of her life. The manuscript of Harp Song for a Radical: The Life and Times of Eugene Victor Debs, was unfinished at the time of her death but was published by Alfred A. Knopf in 1999. Inviting the Muses, a collection of her stories, essays, and reviews, appeared in 1994.