In 1670 he was appointed Knight of the Golden Fleece by Charles II of Spain.
He was Captain General of the Cavalry and Extraordinary Spanish Ambassador in England (1678-1679).
At the start of his reign, the island suffered from a lack of food and resources.
The Count of Egmont died in March 1682, after a long illness, leaving Sardinia as oppressed by hunger as at the beginning.
He was replaced in the position of Viceroy by Fray Diego Ventura Fernández, Archbishop of Cagliari.