After graduating from
University of Lisbon's
Instituto Superior Técnico in 1953, at the age of 23, with an engineering degree in industrial chemistry she went into a graduate scholarship program with the national Nuclear Energy Board. After completing the program, she began working for a large Portuguese conglomerate with interests in cement plants,
Companhia União Fabril, the "CUF". By 1954, she held the position of chief engineer of the studies and projects division. From that position she quickly moved to the position of project director, where she was in charge of the firm's documentation center and responsible for the company's technical journals. She held this position for seven years, until she left the company in 1960. Pintasilgo had strong ties to the
Roman Catholic Church. From 1952 to 1956, at Lisbon's
Catholic University of Portugal, she was president of the women's group. In 1956 she became the international president of a movement of Catholic students, Pax Romana. In 1961, Pintasilgo joined the Grail (Graal), an international Catholic laywomen's movement. Two years after joining the Grail she led an international group working to improve the movement as well as establishing it in Portugal. By 1965 she had become the Grail's international vice-president. She was also appointed by the Vatican and served as woman's liaison between the Roman Catholic Church and the
World Council of Churches. After leaving
Companhia União Fabril, she held a job in government until 1969 which was to run Portugal's program for development and social change. In 1970, she presided over government working groups involving women's affairs, as well as being a member of the Portuguese delegation to the United Nations, 1971–72. In 1974 she was appointed secretary of state for social welfare in the first provisional government following the revolution. She moved her way up to Minister of Social Affairs by early 1975. In 1975, Pintasilgo became Portugal's first Ambassador to the United Nations Educational, Scientific and Cultural Organization, UNESCO. == Tenure as Prime Minister and later career==