In this sense, the prime minister establishes the Government policies and coordinates the actions of the Cabinet members.

Although it is not possible to determine when the position actually originated, the office of prime minister has evolved throughout history to what it is today.

Upon a vacancy, the monarch nominates a candidate for a vote of confidence by the Congress of Deputies, the lower house of the Cortes Generales.

[4] Pedro Sánchez, of the Spanish Socialist Workers' Party (PSOE), has been prime minister since 2 June 2018.

[5] Since then, Sánchez has led three governments, the most—along with Adolfo Suárez—just behind fellow socialist Felipe González, prime minister from 1982 to 1996.

[6] King Felipe VI re-appointed Sánchez for the third time on 17 November 2023[7] after he reached a coalition agreement with Sumar and gathered the support of other minor parties.

Before 1834 the figure was known as "Secretary of State" (Secretario de Estado), a denomination used today for junior ministers.

Spain was not unique in this regard: it was one of several European parliamentary systems, including France, Italy and the Irish Free State, that styled the head of government as 'presidents' of the government rather than the Westminster term of 'prime minister' (see President of the Council for the full list of corresponding terms).

Following the abdication of King Amadeus I, during the First Republic (1873–1874) the office was known as the President of the Executive Power and was also head of state.

With the fall of the First Republic and the restoration of the Bourbon dynasty on King Alfonso XII, the office maintained its original name until the dictatorship of Primo de Rivera, when it was renamed to President of the Military Directory.

He was originally appointed by King Juan Carlos I on 3 July 1976, and he was confirmed in the office by popular vote after the 1977 Spanish general election.

Following the general election and other circumstances provided for in the Constitution, the sovereign meets with the leaders of the parties represented in the Congress of Deputies, and then consults with the Speaker of the Congress of Deputies (Spanish: Presidente de Congreso de los Diputados) as representative of the whole of parliament), before nominating a candidate for the prime ministership.

[22] If, within two months, no candidate has won the confidence of the Congress then the monarch dissolves the Cortes and calls for a new general election.

[22] During the swearing-in ceremony presided over by the monarch, customarily at the Audience Hall of the Royal Palace of Zarzuela, the prime minister–designate takes an oath of office over an open Constitution and—at choice since 2014[26]—next to a Bible and a crucifix.

Currently, only one prime minister has refused to take the oath of office next to religious symbols: Pedro Sánchez, along with most of his Cabinet members.

The government conducts domestic and foreign policy, civil and military administration, and the defense of the nation all in the name of the monarch on behalf of the people.

However, Section 56 of the Constitution vests the monarch as the "arbitrator and moderator of the institutions" of government, [The King] arbitrates and moderates the regular functioning of the institutions (arbitra y modera el funcionamiento regular de las instituciones).

[29][30] This provision could be understood as allowing the monarch or his government ministers to exercise emergency authority in times of national crisis, such as when the monarch used his authority to back the government of the day and call for the military to abandon the 23-F coup attempt in 1981.

[36] The Cabinet Office, through the General Secretariat of the Presidency of the Government, is responsible for the protocol and security affairs.

Also, if at the conclusion of the four years, the prime minister has not asked for its dissolution, according to Title II Section 56, the monarch must dissolve the Parliament and call for a new general election.

If the censure motion is successful, the replacement candidate is automatically deemed to have the confidence of the Congress, and the monarch is required to appoint them as the new prime minister.

As of 2023, only prime minister Adolfo Suárez in 1980 and Felipe González in 1990 proposed a vote of confidence, both successfully.

Although the Prime Minister does not have legal immunity like the monarch, the prime minister, as well as the members of the Royal Family, the Government, the Congress of Deputies and the Senate, can only be criminally responsible before the Criminal Chamber of the Supreme Court (Spanish Constitution, Part IV § 102).

Although the position of deputy prime minister has existed intermittently since 1840, the Constitution endorses what was established in the Organic Act of the State of 1967,[48] which provided for the first time the possibility of appointing more than one deputy and, in 1974, this provision became effective when Prime Minister Carlos Arias Navarro appointed three deputies (José García Hernández, Antonio Barrera de Irimo and Licinio de la Fuente).

[49] Since then, three more prime ministers (Adolfo Suárez, José Luis Rodríguez Zapatero and Pedro Sánchez) have had more than one deputy.

[57][58] This is because the prime minister is, since he is appointed as such by the sovereign, a Knight or Dame Grand Cross of the Order of Charles III, for which he is awarded the next highest distinction.

In addition to these honors, the monarch might offer the former prime minister a peerage,[59] being the highest marks of distinction that he may bestow in his capacity as the fons honorum in Spain.

[60] King Juan Carlos I wanted to restore this tradition and, therefore, as a reward for their service, the last noble titles granted (both with grandship) were those of Adolfo Suárez (to whom the golden fleece was also awarded in 2007[61]), who was created Duke of Suárez in 1981[62] and Leopoldo Calvo-Sotelo, created Marquess of the Ría de Ribadeo [es] in 2002, twenty years after holding the office.

In 1983, the first government of Felipe González established the "Statute of Former Prime Ministers", which granted retired prime ministers, for four years, the right to have an office composed by two civil servants, a minimum endowment of 2.5 million pesetas each year for office expenses and an official vehicle with driver.

[65] Nine years later, the government updated the Statute, removing the time limit the prime minister would receive privileges, including diplomatic assistance abroad, security, a personal salary for two years after leaving the office and, free pass in public transportation and an undetermined endowment for office expenses.