Professor Harrison received his doctorate in romance studies from Cornell University in 1984, with a dissertation on Dante's Vita Nuova. In 1985 he accepted a visiting assistant professorship in the Department of French and Italian at Stanford. In 1986 he joined the faculty as an assistant professor. He was granted tenure in 1992 and was promoted to full professor in 1995. In 1997 Stanford offered him the Rosina Pierotti Chair. In 2002, he was named chair of the Department of French and Italian. He is also lead guitarist for the cerebral rock band Glass Wave.

Professor Harrison's first book, The Body of Beatrice, was published by Johns Hopkins University Press in 1988. A revised and elaborated version of his dissertation, it deals with medieval Italian lyric poetry, with special emphasis on Dante's early work La Vita Nuova. The Body of Beatrice was translated into Japanese in 1994. Over the next few years Professor Harrison worked on his next book, Forests: The Shadow of Civilization, which appeared in 1992 with University of Chicago Press. This book deals with the multiple and complex ways in which the Western imagination has symbolized, represented, and conceived of forests, primarily in literature, religion, and mythology. It offers a select history that begins in antiquity and ends in our own time. Forests appeared simultaneously in English, French, Italian, and German. It subsequently appeared in Japanese and Korean as well. In 1994 his book Rome, la Pluie: A Quoi Bon Littérature? appeared in France, Italy, and Germany. This book is written in the form of dialogues between two characters and deals with various topics such as art restoration, the vocation of literature, and the place of the dead in contemporary society. Professor Harrison's next book, The Dominion of the Dead, published in 2003 by University of Chicago Press, deals with the relations the living maintain with the dead in diverse secular realms. This book was translated into German, French and Italian. Professor Harrison's most recent book is Gardens: An Essay on the Human Condition, which appeared in 2008 with the University of Chicago Press, and in French with Le Pommier. In 2005 Harrison started a literary talk show on KZSU radio called "Entitled Opinions." The show features hour long conversation with a variety of scholars, writers, and scientists.