Born in Winnipeg, Canada, Cantor received his B.A. at the University of Manitoba in 1951. He went on to get his master's degree in 1953 from Princeton University and spent a year as a Rhodes Scholar at the University of Oxford. He received his doctorate from Princeton in 1957 under the direction of the eminent medievalist Joseph R. Strayer.

After teaching at Princeton, Cantor moved to Columbia University from 1960 to 1966. He was a Leff professor at Brandeis University until 1970 and then was at SUNY Binghamton until 1976, when he took a position at University of Illinois at Chicago for two years. He then went on to New York University, where he was professor of history, sociology and comparative literature. After a brief stint as Fulbright Professor at the Tel Aviv University History Department (1987—88), he devoted himself to working as a full-time writer.

Although his early work focused on English religious and intellectual history, Cantor's later scholarly interests were far more diverse, and he found more success writing for a popular audience than he did engaging in more narrowly-focused original research. He did publish one monograph study, based on his graduate thesis, Church, kingship, and lay investiture in England, 1089-1135, which appeared in 1958 and remains an important contribution to the topic of church-state relations in medieval England. Throughout his career, however, Cantor preferred to write on the broad contours of Western history, and on the history of academic medieval studies in Europe and North America, in particular the lives and careers of eminent medievalists. His books generally received mixed reviews in academic journals, but were often popular bestsellers, buoyed by Cantor's fluid, often colloquial, writing style and his lively critiques of persons and ideas, both past and present. Cantor was intellectually conservative and expressed deep skepticism about what he saw as methodological fads, particularly Marxism and postmodernism, but also argued for greater inclusion of women and minorities in traditional historical narratives. In both his best-selling Inventing the Middle Ages and his autobiography, Inventing Norman Cantor, he reflected on his strained relationship over the years with other historians and with academia in general.

Upon retirement in 1999, Cantor moved to Miami, Florida, where he continued to work on several books up to the time of his death.

• The Medieval World 300-1500 ('Norman Cantor, Civilization of the Middle Ages, p. 2')
• Perspectives on the European Past
• The Civilization of the Middle Ages (a revision of his earlier Medieval History: the Life and Death of a Civilization 1963)
• How to Study History (with Richard I. Schneider), 1967, a textbook that lays out fundamental methods and principles, including the uses of primary and secondary sources.
• The English
• Western Civilization: Its Genesis and Destiny
• The Meaning of the Middle Ages
• Inventing the Middle Ages : The Lives, Works and Ideas of the Great Medievalists of the Twentieth Century, 1991, a historiography of views of the Middle Ages, in twenty vitae of seminal historians and other shapers of contemporary perception, including C. S. Lewis and J. R. R. Tolkien: "Any bright American college sophomore who today takes a good survey course on medieval history has a better understanding of the components of the medieval world than anyone who wrote before 1895" wrote Cantor.
• Medieval Lives
• Medieval Society, 400-1450
• Twentieth Century Medieval Culture
• The Sacred Chain: History of the Jews, Published by Harper/Collins, 1994
• Varieties of Culture in Modern Times, 1997
• In the Wake of the Plague: The Black Death and the World It Made, 2001
• Antiquity, 2003
• The Twilight of the Middle Ages and the Birth of the Modern Era, 2004 (The subject is John of Gaunt)
• Alexander the Great, Published posthumously by HarperCollins in 2005

Cantor published a memoir in 2002, Inventing Norman Cantor: Confessions of a Medievalist.