The first reference of the place is found in a document of Gregorio III, Count of Tusculum, in the 11th century, when the Chiesa di Sant’Antonio in Monte Porculo was given to the Benedictines of Montecassino Monastery.
The name almost certainly comes from Mons Porcii, which in turn comes from the Gens Porcia dei Catoni who had a villa in the area. Further mention of the locality is in the papal bull of Pope Gregory VII in 1074, where Monte Porculi is indicated as a property of the Monastero di San Paolo fuori le mura.
In the 15th century, the Castle of Monteporzio was handed over to Teodobaldo degli Annibaldi family to support Pope Boniface IX in the conflicts with Niccolò Colonna di Palestrina, who opposed the Church.
However, it was thanks to Cardinale Marco Sittico Altemps that Monteporzio began its urban development, which was continued throughout the 17th century by the Borghese family, after the donation in 1616. They built their palace and had the church dedicated to San Gregorio Magno completely rebuilt, in honour of Pope Gregory VIII.