 Butler worked at the Newberry Library in Chicago from 1916 to 1919, and went on to lead its John M. Wing Foundation on the History of Printing.In that position he built the collection of the Newberry into one of the great research libraries for international scholarship in the United States, through extensive international travel to acquire hard-to-find books.In 1931, Butler became a professor of bibliographic history at the Graduate Library School (GLS) of the University of Chicago (the same year that "The Library Quarterly" was founded there).