He studied history and philosophy and graduated in 1956 from the University of Lisbon with a thesis entitled A Sociedade em Portugal nos Séculos XII a XIV (Portuguese Society from 12th to 14th Centuries).
In 1962, his participation in student strikes against the right-wing regime of Oliveira Salazar resulted in his dismissal from the university as a scholar.
He left for the United States where he taught history at a number of universities (Auburn, Florida, Columbia, Minnesota and Chicago) between 1965 and 1970.
Oliveira Marques returned to Portugal in 1970, but only resumed teaching at Portuguese universities in 1974, the year in which the Carnation Revolution ended almost five decades of the Estado Novo regime.
In 1998, he was granted the Grand Cross of the Order of Liberty, a state accolade which distinguishes figures who have made a contribution to the values of civilization.