Keogh started his library career as a librarian with the Newcastle-upon-Tyne Public Library in England from 1892-1898. He then became librarian of the Linonia and Brothers Library at Yale University in 1899 and became a reference librarian at the Yale University Library from 1900 to 1916. He was promoted to head librarian at Yale in 1916 and served in that position until his retirement in 1938. Keogh served as president of the American Library Association from 1929 to 1930.
