He went to India in 1721 as an officer of the French East India Company. In 1731 he was appointed governor of Chandannagar, where he made a considerable fortune, and in 1742 he became governor of Pondichéry and was thus the chief official in French India. When the War of the Austrian Succession brought the French and British East India companies into conflict, Dupleix supervised the capture of Madras (1746) and successfully defended Pondichéry, but the Treaty of Aix-la-Chapelle (1748) restored the prewar situation. Dupleix then formed a vast project for establishing French supremacy in India.
Intervening in native politics, intrigues, and warfare, he controlled the Carnatic and nearly the entire Deccan by 1751. Soon, however, the British began to regain ground under the leadership of Robert Clive, and the French government, anxious to avoid war and uninformed of Dupleix’s grandiose schemes, recalled the governor in 1754. With Dupleix, the last hope of a French empire in India vanished. He ended his days in poverty and neglect.