He served with distinction under Joseph François Dupleix in the East Indies, receiving the Order of Saint Louis.

He contributed to the recovery from Britain of Pondicherry in 1748, and was named in 1782 to lead all French military forces beyond the Cape of Good Hope.

He coordinated his operations with Pierre André de Suffren and fought against the British during the Indian campaigns of the American War of Independence.

The Yanam region was presented to the Marquis de Bussy, the French General by Vizianagaram King Pusapati Peda Vijaya Rama Raju (1670–1756) as a token of gratitude for the help he had rendered in the fight against the rulers of Bobbili.

On 23 November 1753, a Paravana of Asif ad-Dawlah Mir Ali Salabat Jang, Subedar of Deccan conceded to Marquis de Bussy-Castelnau the paraganas of Chicacole, Ellore, Rajahmundry etc.

with an annual revenue ₹2,00,000 for the maintenance of the French troops in the Subah in recognition of the help of these Circars amounted up to 10 lakhs of Rupees per year.

In the year 1755, De Bussy received letter from the newly ordained Mughal Emperor Alamgir II requesting French assistance to put down the Maratha Confederacy.