This position has no executive authority although it is the principal advisor to the Prime Minister and it coordinates the work action of the different departments of the Government as well as lead the Cabinet Office.

The current position is regulated in the Royal Decree 419/2018, of June 18, which restructures the Prime Minister's Office.

The first time that this position was created was in 1976, when Carmen Díez de Rivera was appointed Chief of Staff, however, the role was not regulated until 1978, when a short Prime Minister's order integrate it in the Prime Minister's Office and gave it rank of Undersecretary.

[3] PM José Luis Rodríguez Zapatero continue expanding the powers of the Chief of Staff giving him competences over the protocol and security departments of the Prime Minister's Office as well as entrusting him with advice on economic matters.

[4] With PM Rajoy the Chief of Staff reached the height of its power when he was granted with the supervision over the sanitary system of the prime minister's office and with powers over national security matters, when the Deputy Chief of Staff was also named Director of the Homeland Security Department.