State librarian After graduating from college, Ahern worked as an Indiana public school teacher until 1889, when she was appointed as the Indiana assistant state librarian. Ahern's early work at the state library included cataloging its collections. In 1893 the
state legislature appointed Ahern as the Indiana state librarian, a political position that she retained until 1895.
Journal editor After completing her library studies in Chicago, Ahern accepted a position as the founding editor of a new journal,
Public Libraries (later shortened to
Libraries). She edited the journal from her base in Chicago for the next thirty-six years. Deteriorating eyesight forced her to give up her editorship in 1931. She further argued that a public library could provide the best source of this education because it "is the broadest of teachers, one may almost say the only free teacher. It is the most liberal of schools; it is the only real people's college." Ahern became an influential authority on public policy issues related to libraries through her writing and public appearances across the county. She described her vision for public libraries, as well as providing practical professional development resources for libraries, and influenced librarians and library practice throughout the United States. Ahern also served in the federal government and as secretary of the Library Department of the
National Education Association. During
World War I she served as publicity agent and distributed books for the U.S. military in
France from January to July 1919. Ahern continued to learn and advocate for changes in library policy. In 1927 she returned to Europe to study the library systems in France and
England. ==Death and legacy==