The Under-Secretary is responsible for assisting the Minister in his duties to support the Prime Minister, preparing the meeting of the Council of Ministers and other governmental meetings, coordinating and directing the common services of the department, controlling the economic, human and technological resources of the Ministry, elaborating the governmental regulations, giving authorization for the use of the Coat of Arms, Flag and other symbols of the State and the competences about the ministry's gender equality and transparency.

It received the official name of Undersecretariat of the Presidency of the Council of Ministers and its first holder was Alejandro Shee y Saavedra.

[4] On July 19, 1951 the Undersecretariat was elevated to Ministry and Luis Carrero Blanco was appointed the Minister-Under Secretary of the Presidency.

[5] Around 1974, the Undersecretariat lost its ministerial level when the Ministry of the Presidency was officially created and the first was subordinated to it.

In 2020, the Ministry lost its responsibilities on equality but acquired those on democratic memory and religious freedom.