This Secretariat of State was in charge of all affairs relating to negotiations (treaties, weddings and alliances), communication with foreign rulers in matters of peace and war, and with the sending of diplomatic agents abroad.

[2] Foreign Affairs and War were kept in the same Secretariat, except for an ephemeral split from 6 January to 28 July 1801, until 1820, when an Ordinance of the Provisional Junta of the Government, issued on 27 September of that year, determined its separation in two distinct branches of the Public Administration.

The Ministry has the responsibility of ensuring the representation of the Portuguese State in other countries and international organizations, through its External Network of embassies, permanent missions, and consular posts.

During his time as Minister of Foreign Affairs, José Manuel Durão Barroso summarized the role of the Ministry by describing it as "the expert on political issues, tough concomitantly a generalist is all issues – economic, cultural, or of other kinds – which in any way are relevant in the defense or the promotion of our interests in the international sphere".

Besides its External Network, the MFA has central services operating from the Palácio das Necessidades in Lisbon, whose function is to define Portugal's external policy in the bilateral and multilateral fields, in European affairs and in consular issues (including offices in Lisbon and in Porto established to assist and legally recognize documents to Portuguese citizens living abroad).

[3] The Ministry of Foreign Affairs has competences over the following integrated services in the direct administration of the State, integrated organisms under indirect administration of the State, advisory bodies and other structures:[5] The history of the Minister of Foreign Affairs position dates to 15 March 1830, with the establishment of the liberal Regency in Terceira Island, in the context of the Liberal Wars.

In that same date Luís Mouzinho de Albuquerque was nominated as Minister and Secretary of State of Foreign Affairs.