Ellen was a lecturer at the San Jose State University School of Information, as well as the Information School at the University of Wisconsin, Madison, where she specialized in courses dealing with library services to LGBTQ communities and diverse populations. Ellen retired after many years as Associate Dean for Access, Collections, and Technical Services at Auraria Library, Denver, Colorado and had also worked as a Head of Authority Control at the State University of New York at Buffalo Library and Head of the Romance Languages Team at Princeton University Libraries. Greenblatt co-edited, with Cal Gough, the groundbreaking Gay and Lesbian Library Service (1990, McFarland). The book, the first of its kind, provided librarians concrete strategies “in selecting books and improving services” for LGBTQ patrons. A longstanding and vocal advocate for LGBTQ librarianship, Greenblatt co-chaired the ALA GLBT Round Table, and served on a number of advisory boards, including the Center for Lesbian and Gay Studies (CLAGS) International Resource Network.