Garretón studied Sociology in the Catholic University of Chile and graduated in 1967. He received his PhD at the "École des Hautes Études en Sciences Sociales" of Paris. He directed the Catholic University of Chile's Centro de Estudios de la Realidad Nacional (CEREN) from 1970 until its closing in 1973. He also edited CEREN's journal "Cuadernos de la Realidad Nacional" during those same years. In 1973, he was the Dean of the Area of Interdisciplinary Social Studies at the Catholic University. After the 1973 military coup, Garretón coordinated emergency groups in the social sciences in Chile. Between 1975 and 1995 he was at the Facultad de Ciencias Sociales (FACSO), Chile, as Research Professor. Since 1994 Garretón has been full professor at the Department of Sociology, School of Social Sciences, at the University of Chile.