Cornejo Polar was born December 23, 1936 in Arequipa, Peru. He received a PhD from the National University of San Agustin in Arequipa, became a professor there as well, then in 1966 he becomes Professor in National University of San Marcos, Lima. He was also a visiting professor at the University of Pittsburgh and UC Berkeley.

He authored 11 books, and was considered an authority on Latin-American literature and culture. He was also the founder and editor of the Revista de Critica Literaria Latinoamericana, a journal which covered issues of culture and ideology in Latin-American literature.

Cornejo-Polar was married to Cristina Soto, who worked with him on the journal, and also managed "Latinoamericana Editores", a publishing company which covers Latin-American topics. They had four children Ursula, Alvaro, Gonzalo and Rafael and four grandsons Gonzalo, Juán Diego, Antonio y Natalia.

He died after a long illness on May 18, 1997, in Lima.