He entered the navy as a midshipman in 1698, and received his first command (of the privateer ship Argonaute) in 1708.

Following a promotion to sub-lieutenant, he fought at Rio de Janeiro in 1711 during the War of the Spanish Succession.

Dubois de La Motte was promoted to captain in 1738, and directed three campaigns in the West Indies.

He served extensively off the coast of North America, including being assigned to help defend Louisbourg, on Cape Breton Island, in the Seven Years' War.

In 1758, with his active career over (at 75 years of age), he participated in a battle to repulse a British landing near Saint-Malo, which ultimately proved successful.