Mercedes de la Garza studied Spanish literature at the National Autonomous University of Mexico (UNAM) from 1957 to 1962. She earned a master's degree in the history of Mexico and a Ph.D. in history. She also took graduate and postgraduate courses at the Complutense University, El Escorial, University of Toulouse, Pennsylvania State University, and King Juan Carlos University. She taught Spanish language and history of ancient cultures in private schools from 1963 to 1975. Since 1973, she has taught courses on the culture of the Mayan and Nahua peoples in the Faculty of Arts of UNAM, the Antiguo Colegio de San Ildefonso, the National Museum of Anthropology in Mexico City, the Universidad Iberoamericana, Casa America in Madrid, and El Escorial, among others. She has created master's and doctoral studies on Mesoamerican peoples. From 1997 to 2000, she was director of the National Museum of Anthropology. She was elected to the Mexican Academy of Sciences in 1977, and the Mexican Academy of History in 2005.