[1] During the Nine Years' War, Aerssen participated in the defence of the Dutch colony of Surinam against an attack by a French Navy fleet commanded by Admiral Jean-Baptiste du Casse in 1690.

He also participated in the battles of Barfleur and La Hougue, and Lieutenant-Admiral Gerard Callenburgh held him in high regard due to his skills as a naval officer.

[2] He was promoted to the rank of Schout-bij-nacht in the next year, passing over Philip Schrijver and Cornelis Beeckman, both of whom had were highly meritorious officers, something which was attributed by his contemporaries to Aerssen's aristocratic background.

[2] In 1709, leading a Dutch squadron, Aerssen joined forces with elements of the British Royal Navy led by Vice-Admiral John Norris in the Mediterranean Sea to carry out operations against the French, though he was "not in a position to do much".

He subsequently participated in an Anglo-Dutch landing operation in Southern France, near Sète, which allowed for Grand Alliance troops to attack targets in the region in conjuction with French émigrés.