[2] He garnered acclaim for this book, as well as criticisms from more conservative historians discomfited by the work's nationalist bent.

In 1958, Agoncillo was invited to join the faculty of the Department of History of his alma mater, the University of the Philippines.

After retiring from UP, Agoncillo taught Filipino history as a visiting professor at the International Christian University in Mitaka, Tokyo, Japan, for one year from 1977 to 1978.

Philippine President Diosdado Macapagal named Agoncillo as a member of the National Historical Institute in 1963.

Gregorio Zaide, Teodoro Agoncillo, Reynaldo Ileto and Renato Constantino stand as the most prominent 20th-century Filipino historians to emerge during the post-war period.