Keller began his academic career at the Music Library, State University of New York at Buffalo as Assistant Librarian for Reference and Cataloging from 1970 to 1973. From 1973 to 1981, he was Music Librarian and Senior Lecturer in Musicology at
Cornell University, where he was also Acting Undergraduate Librarian in 1976. From 1981 to 1986, he was Head of the Music Library,
University of California at Berkeley. In 1984, he was also a Visiting Lecturer in the Department of Music, Stanford University. From 1986 to 1993, he was Associate University Librarian and Director of Collection Development at
Yale University. Keller became a Director at Stanford Libraries in 1993. In 1994, he was named the Ida M. Green University Librarian and Director of Academic Information Resources. From 1995 to 2014, he also served as Founder and Publisher for HighWire Press, and beginning in 2001, as Publisher for Stanford University Press. Keller has served on more than sixty-five boards, advisory committees, and professional organizations. He is currently Chairman,
International Image Interoperability Framework Consortium (2015 to the present); Member, Board of Directors,
Council on Library and Information Resources (2013 to the present); Member, Board of Trustees,
Kistler-Ritso Foundation (United States and
Estonia) (2010 to the present); and Emeritus Member of the Board of Directors,
The Long Now Foundation. At the
National Academies of Sciences, Engineering, and Medicine Keller was an appointed member on the Steering Committee for the Initiative on the Informed Brain in the Digital World (2011-2014), the Committee to Develop a Research Agenda on Copyright & Innovation, Science (2010-2011), the Committee on Scientific Responsibility (2009-2016), and the Board on Research Data and Information (2009-2011). He was Founding Member, President, and Chairman of the National Digital Library Federation (1994-2007). At Stanford, Keller served as a University Fellow (1994-1995) and on the Academic Senate ex-officio (1993-2010), Commission on Technology in Teaching and Learning (1994-1998), and President's Cabinet (1994 to the present). He was an Alumni Trustee at Hamilton College (2001-2005) and a member of the Consultative Board at the
British Library (2009-2011). Keller’s honors and awards include Elected Fellow,
American Association for the Advancement of Science (2009 to the present); Elected Fellow,
American Academy of Arts and Sciences (2010 to the present); Minerva Award, SUNY/Geneseo (2011); Sarum Canon, Salisbury Cathedral, Wiltshire, United Kingdom (2014 to the present); Kenneth M. Cuthbertson Award for Exceptional Service to Stanford University (2015); Order of the Cross of Terra Mariana, Fourth Class, Estonia (2016); and Honorary Fellow for Life, Harris Manchester College at Oxford University (2019). ==Research==