MARIANNE MOORE was born in Kirkwood, Missouri, in the manse of the Presbyterian church where her maternal grandfather, John Riddle Warner, served as pastor. She was the daughter of construction engineer and inventor John Milton Moore and his wife Mary Warner. She grew up in her grandfather's household, her father having been committed to a mental hospital before her birth. In 1905 Moore entered Bryn Mawr College in Pennsylvania and graduated four years later. She taught at the Carlisle Indian Industrial School in Carlisle, Pennsylvania until 1915, when she began to publish poetry professionally .

In part because of her extensive European travels before the First World War, Moore came to the attention of poets as diverse as Wallace Stevens, William Carlos Williams, H. D., T. S. Eliot and Ezra Pound. From 1925 until 1929, Moore served as editor of the literary and cultural journal The Dial. This continued her role, similar to that of Pound, as a patron of poetry, encouraging promising young poets, including Elizabeth Bishop, Allen Ginsberg, John Ashbery and James Merrill, and publishing her early work as well as refining her poetic technique. Moore never married.

In 1933 she was awarded the Helen Haire Levinson Prize for Poetry. Her Collected Poems of 1951 is perhaps her most rewarded work; it earned the Pulitzer Prize, the National Book Award, and the Bollingen Prize. Moore became a minor celebrity in New York literary circles, serving as unofficial hostess for the Mayor. She attended boxing matches, baseball games and other public events, dressed in what became her signature garb, a tricorn hat and a black cape. She particularly liked athletics and athletes, and was a great admirer of Muhammad Ali, to whose spoken-word album, I Am the Greatest!, she wrote liner notes.

Not long after throwing the first pitch for the 1968 season in Yankee Stadium, Moore had a stroke. She suffered a series of strokes thereafter, and died on February 5, 1972. She was interred in Gettysburg's Evergreen Cemetery.

 Marianne Moore's living room has been preserved in its original layout in the collections of the Rosenbach Museum & Library in Philadelphia. Her entire library, knicknacks (including a baseball signed by Mickey Mantle), all of her correspondence, photographs, and poetry drafts are available for public viewing. In 1996 she was inducted into the St. Louis Walk of Fame.