- Not to be confused with Cardinal Girolamo Colonna di Sciarra.
Colonna was born at Orsogna into the Colonna family and his extended family included members of various 17th-century Italian royal and noble houses. His father was Filippo I Colonna, Prince of Paliano and his mother was Lucrezia Tomacelli. His sister, Anna Colonna, married Taddeo Barberini, brother of cardinals Francesco Barberini and Antonio Barberini (Antonio the Younger).
After the death of Pope Urban, he participated in the Papal conclave of 1644 that elected Pope Innocent X. He was Archpriest of the patriarchal Lateran basilica and Legate a latere for the opening and closing of the Holy Door in the patriarchal Lateran basilica in the Holy Year of 1650. He took part in the conclave of 1655 that elected Pope Alexander VII.
Pope Innocent X appointed him as Ambassador of the Holy See to Spain. He was called to Spain by King Philip IV and appointed as a counselor on state and military affairs. He celebrated the wedding between Emperor Leopold I and Infanta Margarita of Spain (daughter of Philip IV) and as legate accompanied her to Germany.
He was accompanied to Spain by Jules Mazarin (then-17-years-old; later elevated to Cardinal himself). Mazarin later assisted Colonna's brother-in-law Taddeo and his brothers when they went into exile during the short schism between the Barberini and the Pamphili.
King Philip IV died in 1665 and Colonna assisted in the provision of last rites. At the death of the King, Colonna returned to his native Italy but died on 4 September 1666 at the Dominican convent in Finale Marina, near Genoa.
Letters from Milan and Genoa, dated 15 January 1667, verified the news. After six years, his remains were moved to Rome and buried in the chapel of his family in the patriarchal Lateran basilica.
- Florida International University - Girolamo Colonna
- Worldroots - Barberini
- Pope Alexander the Seventh and the College of Cardinals by John Bargrave, edited by James Craigie Robertson (reprint; 2009)