He fought in the Battle of Nieuwpoort (1600), the Siege of Ostend (1601–1604) and distinguished himself as General of the Artillery in the Frisian campaigns of Ambrosio Spinola.

As a mark of special favour the commandery in the Order of Calatrava that he had to renounce upon entering the Golden Fleece, was transferred to his son.

[4] Shortly after his election, Emperor Matthias invited Bucquoy to take charge of the Imperial Army and he accepted the post in August 1614.

Defeated by Count Jindřich Matyáš Thurn on 9 November in the Battle of Lomnice, he was unable to save the besieged town of Pilsen.

Bucquoy was killed during the siege of Neuhäusel Fortress (Hungary: Érsekújvár, Latin: Novum Castrum, today Nové Zámky, Slovakia) on 10 July 1621.