Anna Harriet Heyer was born on August 30, 1909 in Little Rock, Arkansas. Her parents were both alumni of the University of Cincinnati, where her mother majored in Latin and Greek, and her father in civil engineering. Her mother went on to receive a degree from the library school at Western Reserve University. The family relocated several times, living in Kansas City, Missouri, Washington, D.C., and ultimately Fort Worth Texas. Heyer, who throughout her life was addressed or referred to as Miss Heyer, attended Texas Christian University, where she graduated in 1930 with a major in math and a minor in piano. She taught briefly in Fort Worth public schools, but continued her education in librarianship at the University of Illinois at Urbana-Champaign. She returned to Fort Worth as a school librarian for much of the 1930s. An article by Otto Kinkeldey in the ALA Bulletin inspired her to investigate music librarianship, and she obtained a master's degree in library science from Columbia University in 1939, studying with Richard Angell. Heyer again returned to Texas, and accepted a position at the University of Texas at Austin in the fall of 1939. Heyer joined the faculty of what is now the University of North Texas in 1940, recommended by Columbia to administrators seeking a music librarian. The Music Library was thus co-founded by Heyer and School of Music dean Wilfred Conwell Bain in 1941.
Heyer was the first full-time music librarian in Texas, and built the Music Library into one of the largest in the country, with considerable holdings of rare and antiquarian music books. Her publications had a wide impact on the field of music librarianship, particularly her Historical Sets, Collected Editions and Monuments of Music: A Guide to Their Contents, first published in 1957, with further editions in 1969 and 1980.
Heyer served as music librarian at North Texas until 1965, when she decided to return to Fort Worth following the death of her mother. She also returned to Texas Christian University, nominally as a consultant on music library materials, but she cataloged thousands of music materials and ran the music library for fourteen years. Heyer died in Fort Worth on August 12, 2002, just before her ninety-third birthday.