Peggy Johnson began her library career as a music cataloguer and has been a children's librarian in a public library, and serials cataloguer, technical services head, and a senior collection development officer in academic libraries. In 2002, she served as interim university librarian at the University of Minnesota. Johnson has consulted on library development in Uganda, Rwanda, Morocco, and China. She is a frequent speaker and consultant on collection development and management and on change in libraries, two areas of particular interest. She edits the journal Technicalities: Information Forum for the Library Services Practitioner, has published numerous papers, and written and edited several books.