G. A. Wilkes studied at the University of Sydney. His interest in Australian literature saw him take the unconventional step, in the 1940s and 1950s, of writing BA and MA theses on Australian writers: Henry Handel Richardson and Christopher Brennan, respectively. His MA thesis on Brennan's Poems (1913) was published as a monograph in 1953 and remains a highly respected study. Wilkes published a significant amount of articles on Brennan, but he extended his analyses to many other Australian writers, including A. D. Hope, Patrick White, R. D. Fitzgerald and Judith Wright. Many of these articles drew on the lectures he had developed during the 1960s as foundation professor of Australian literature at the University of Sydney. In addition, his contributions to and his thirty-four year editorship of Southerly drew his attention further into the history of Australian literature. Many studies on the development of Australian literature in the nineteenth century appeared during the 1970s and 1980s, culminating in The Stockyard and the Croquet Lawn: Literary Evidence for Australian Cultural Development (1981). Wilkes argued against restricting Australian nationalism to the ten year period of the 1890s, stimulating much research into the development of nineteenth century Australian culture.