Janet Lowley Lewis was born in Chicago, Illinois, in 1899 and attended the University of Chicago. There, she became friends with Glenway Wescott and Yvor Winters, whom she married in 1926. In 1929, she and Winters founded the literary magazine Gyroscope. She taught at Stanford University and the University of California at Berkeley.
A novelist, short story writer, and librettist, Lewis was best known for her historical novels but also authored several volumes of poetry, including The Dear Past and Other Poems, 1919–1994 (Robert L. Barth, 1994); Janet and Deloss: Poems and Pictures (Brighton Press, 1990); and Poems Old and New, 1918–1978 (Swallow Press, 1981). Many of her poems reflect her fascination with the Southwest and Native Americans.
Lewis died in Los Altos, California, in December 1998, at the age of ninety-nine.