He attended the La Guardia Jesuit High School before enrolling at the Faculdade de Ciências da Universidade de Lisboa to study Chemistry. António never finished his college education, for at 19, after his father's death, he took over the family's construction company. Later, at the age of 28 he took over his uncle's (Henrique de Araújo de Sommer, one of Portugal most important industrialists, who had died without issue, as did two of his brothers, two of his sisters and his niece) cement business.