[4] He was named Bishop of Pamplona by the Emperor, an appointment confirmed by Pope Paul III in consistory on 21 May 1539.
Bishop Pedro Pacheco de Villena was made a cardinal by Pope Paul III at the consistory of 16 December 1545.
[7] He took part in the 1549–50 conclave which elected Cardinal Giovanni Maria Ciocchi del Monte as Pope Julius III.
[8] In 1553 Cardinal Pacheco was made viceroy of Naples by Charles V. He served from 1553 to 1555, until the election of Pope Paul IV (Carafa).
[13] He took part in the conclave of 1559 which elected Cardinal Giovanni Angelo de' Medici as pope Pius IV.
[14] In the same year he was made one of the six Cardinal Inquisitors of the tribunal of the Universal and Roman Inquisition in Rome by Pius IV.
[15] His body was later transferred to the Puebla de Montalban, where it was interred in the Convent of the Franciscans (S. Chiara), which he had founded.