Except for the brief periods of the first Republic and the Second Republic, Spain was always under the rule of its monarch, who was the supreme ruler of the state, enjoying the full powers of his sovereignty. Franco himself had come to occupy power in Spain only with the support of the monarchists, and, because he could not leave behind a successor, he chose Juan Carlos as his official heir in 1969. On 22 November, following Franco's death, the Cortes Generales proclaimed Juan Carlos King of Spain, and on 27th November 1969 he ascended the Spanish throne.

Franco had intended Juan Carlos to be his heir both in letter and spirit, continuing with his Fascist tendencies. But Juan Carlos began his regime by instituting many reforms that were contrary to the spirit of Franco. Ultimately, under the new constitution of 1978, Juan Carlos relinquished absolute power and transformed the Spanish government into a Constitutional Monarchy. Today, the monarch of Spain is the head of the state of Spain, the commander-in-chief of its armies and the head of the Ibero-American States Organization.

The monarch of Spain also supervises the regular functioning of state institutions. The power of the monarch of Spain is very much symbolic – he is merely the titular head of state – because all legislation must be countersigned by either the Prime Minister of Spain or the Cortes. The monarch cannot exercise his discretion to block or encourage legislation. The monarch’s tasks are of a neutral and apolitical nature. He convenes and dissolves the Cortes and calls for elections and for referenda. He appoints the prime minister after consultation with the Cortes and names the other ministers based upon the recommendations of the prime minister. He also ratifies civil and military appointments. The duties and privileges of the monarch of Spain have been established by Title II, Articles 56-65 of the Spanish Constitution of 1978. The constitutional title for the monarch of Spain is simply “King of Spain.”

The current monarch of Spain has, however, successfully transcended many of the limitations to act as true leader of his country. He has ensured the smooth transition from dictatorship to democracy, has stood for political stability, and has become a unifying figure in Spanish history. He has played a vital role in foreign relations by making many trips abroad, even to former Spanish colonies, and has engaged in meaningful dialogue with the world’s leaders. Polls from 2000 show that he is widely popular among the Spaniards. In 2008 he was considered the most popular leader in all Ibero-America.

As has already been mentioned, the reigning monarch of Spain is King Juan Carlos, and Prince Felipe is the current heir apparent. The 1978 Constitution allows a female to inherit the throne, but only if there are no other male heirs. If there are neither male nor female heirs, then the successor to the throne is chosen by the Cortes Generales.