Domingos Fezas Vital graduated from the Federal University of Rio de Janeiro, Brazil, with a bachelor's degree in social and judicial sciences. He then studied international trade at the Free University of Brussels. Shortly after, in 1983, he joined the Portuguese Ministry of Foreign Affairs, where he started his diplomatic career as an attaché.

Throughout his diplomatic career, Fezas Vital has held posts not only in embassies but also in international organizations, of which Portugal is a member, namely as a Portuguese representative to NATO and the Western European Union.

In 1996, three years before the transfer of sovereignty over Macau, he was appointed diplomatic adviser to Governor Vasco Joaquim Rocha Vieira. After his posting in Macau, Ambassador Fezas Vital returned to Portugal to work in the Ministry of Foreign Affairs until he was appointed Consul General of Portugal in São Paulo in 2000.

In 2010, he was appointed Ambassador, and in March 2012 he became the Representative of Portugal to the European Union, a post he held until being posted to the US as Ambassador of Portugal. After serving in the United States, Domingos Fezas Vital was appointed, in 2021, Portuguese Ambassador to the Holy See.