John Barnes completed an MA on Joseph Furphy's Such is Life in 1960, publishing, in due course, several important guides for readers of the novel. After working at the University of Melbourne for a short time, he travelled to Cambridge University, where he received an MA. In the late 1960s, he worked at the University of Western Australia, but by 1970, he had returned to Melbourne to teach at La Trobe University, where he introduced the university's first courses in Australian literature.
Barnes has published many articles and several books on Joseph Furphy and was co-editor of Bushman and Bookworm (1995), a collection of Furphy's letters. He has also written articles and books on other authors, such as Charles Dickens, Henry Lawson, and Henry Kingsley. His commentary on the discipline of English studies, Border Crossing, appeared in 1991.
Throughout his career, in addition to his own essays and reviews, Barnes has assisted the production of several literary magazines, including Meanjin, Westerly, and Meridian. In 2004, he continued his association with La Trobe University as an Emeritus Professor.