He was the eldest son of Charles II de Lalaing and Margaret of Croÿ (died 1549).

First, he was loyal to the Spanish King, but in 1576 he supported the States-General of the Netherlands and the Union of Brussels (1577).

That year, Philip became commander in chief of the army of the States-General, but was decisively defeated in the Battle of Gembloux (1578).

This and other disputes with the rebels made him sign Hainaut into the Union of Arras (January 1579), and reconcile himself with the King of Spain, under certain conditions.

They only had one daughter, Margaret of Lalaing, who married with Florent of Berlaymont.