Iberville became a sailor at an early age and served as a volunteer under the Chevalier de Troyes in Hudson Bay. In 1686 he began a brilliant career as soldier and sailor, and took part in many expeditions against the English.
Iberville sailed for France in 1697, and was chosen by the Minister of Marine to lead an expedition to rediscover the mouth of the Mississippi River, and to colonize Louisiana, which the English coveted. Iberville's fleet sailed from Brest on 24 October, 1698. On January 25, 1699, Iberville reached Santa Rosa Island in front of Pensacola, founded by the Spanish; he sailed from there to Mobile Bay and explored Massacre Island, later Dauphine. He cast anchor between Cat Island and Ship Island, and on February 13, he went to the mainland, Biloxi, with his brother Bienville. On May 1, 1699, he completed a fort on the north-east side of the Bay of Biloxi, a little to the rear of what is now Ocean Springs. This fort was called Maurepas or Old Biloxi.
In 1706 Iberville captured the island of Nevis from the English, and went to Havana to obtain reinforcements from the Spanish for an attack on the Carolinas. He died in Havana of yellow fever.