He was born on April 11, 1893 in Montana to Augustine Haynes "Doc" Hersey, a newspaper reporter and publisher. The family moved to Washington, D.C. in the late-1890s. While Mrs. Hersey and two daughters stayed at home, "Doc" took Harold with him on globe-trotting reportorial assignments. They visited many places in North America. In 1904-05, they traveled to the Far East for the Russo-Japanese War. The pair traveled extensively in eastern Asia. "Doc" died in D.C. in 1907, leaving Harold with his mother and sisters.
Harold worked at the Library of Congress for eight years while getting a degree from George Washington University at night. About 1914, he married
Merle Williams; they had one child, a daughter Dorothy, Harold Hersey's only offspring. The marriage was brief. (Merle W. Hersey later moved to New York and edited a succession of sex-oriented "girly pulps" from about 1925-36.)
Harold Hersey moved to Greenwich Village, New York, and helped Margaret Sanger launch her journal Birth Control Review. He met Fulton Oursler. In 1917, Hersey teamed up with Arthur Moss to publish The Quill, a literary and satire magazine. He corresponded with
T. Atkinson Jenkins, and Ezra Pound. He was secretary to the
Author's League, and supported Theodore Dreiser in his Genius censorship fight. He visited author
Henry Leverage in Sing Sing.