Thomas Bonner Flanagan, historical novelist, literary critic and educator, was born in Greenwich, Connecticut on November 5, 1923. All of his grandparents were immigrants to the United States from County Fermanagh in Ireland. He attended Greenwich High School. After his studies were interrupted by service in the U.S. Navy during World War II, he graduated from Amherst College in the Class of 1945. He received a Master's degree (1948) and PhD (1959) in French and English literature from Columbia University. Flanagan was an assistant professor of English at Columbia (1949-1960), professor of English at the University of California Berkeley (1960-1978), and professor of English at the State University of New York at Stony Brook (1978-1996). In 1959 he published a scholarly book, The Irish Novelists, 1800-1850, which was based on his doctoral dissertation. He is the author of a trilogy of historical novels set in Ireland: The Year of the French (1979), The Tenants of Time (1988) and The End of the Hunt (1994). Flanagan's literary honors include the National Book Critics' Circle Award.

Tom Flanagan married Jean Parker in 1949 and was the father of two daughters. After retiring from teaching in 1996, he moved to Berkeley, California and continued to write criticism for numerous publications. He died on March 21, 2002 in Berkeley.