Grimaldo was born in Madrid in 1660 to a wealthy family who had gained experience serving in the administration of the colonies of the Spanish Empire.

In 1683 he was admitted into the Order of Santiago as a gesture to his parentage,[1] but while he began to be acknowledged as a rising politician he failed to gain any serious appointment in government until the 1690s when the old dynasty died out.

It was a turbulent era for Spain, as they had been forced to accept the loss of huge amounts of territory (particularly to Austria in Italy, as well as losing Minorca and Gibraltar to Britain).

When the King briefly stepped down in 1724, often attributed to a fit of madness or a desire to be considered a claimant to the French throne, Grimaldo left office with him.

When the King returned after only a year Grimaldo came with him, but was now increasingly in bad health and he was forced to retire from government.