Barnard was born in Vancouver, Washington to Samuel Melvin and Bertha Hoard Barnard. Her father worked in the timber industry; growing up, she saw much of the backwoods in the vicinity as she accompanied her father to logging camps. She graduated from Reed College, just south of the Columbia River in Portland, Oregon, in 1932. Barnard worked for a few years as a social worker for the Emergency Relief Administration, and while curator of The Poetry Collection at the Lockwood Memorial Library ( University of Buffalo, New York) arranged readings and amassed the writing of many modern poets.

Barnard won several Yaddo residencies circa 1936 - 38; some of her first poetry was published during the years 1936 - 1940, in Five Young American Poets, published by New Directions Publishing founded by James Laughlin. She worked from 1945-50 as research assistant for Carl van Doren, biographer of Benjamin Franklin and generalist historian of Americana; she is acknowledged as having done most of the research on a biography of Jane Mecom, Franklin's youngest sister, and his favourite. Van Doren and Barnard had a common interest in the poet Elinor Wylie (Assault on Mount Helicon, p40). Barnard also worked as a freelance writer.

Barnard was mentored via airmail from Italy by Ezra Pound after she sent him six poems, and was introduced to the likes of William Carlos Williams and Marianne Moore. This generated a lifetime of lengthy correspondence with the former in addition to comprehensive instruction on the art of poetry from Pound. The latter encouraged Barnard to visit Europe, meet H.D. (which did not happen despite pressure from Pound), generally witness the continental European scene, and work on her translations of Sappho from the Greek. She returned to Vancouver after fifteen years on the East Coast and continued to write, mostly original poetry and prose, until her death.