This imperious count had been an officer in the French and Venetian armies. In 1672 he obtained the governorship of Canada, in part, to put off his creditors. With the intendant absent 1672-75, he extended his viceregal and military authority to civil matters. His pretensions, such as being the Conseil Souverain's chairman, were resisted by other officials, whom he sometimes exiled or placed in confinement. The clergy were offended by his approval of selling brandy to the Indigenous peoples. After 1675 he conflicted with Intendant Jacques Duchesneau, who had his own faction in the fur trade. The quarrels led to the recall of both officials to France in 1682.
Frontenac gave France a territorial empire acquired in defiance of his instructions. The king and the minister for the colonies told administrators in Canada to confine French settlement to areas with direct maritime links with France, to gather colonists into defensible communities and to occupy settlers in farming and manual trades. The fur trade was blamed for the dispersal of manpower and for the military and economic weakness of New France. Frontenac used his authority to send out exploratory parties and to establish forts - trading posts really - to benefit his confederates in the fur trade. A network of forts appeared on the Great Lakes and along the tributaries of the Mississippi. Denial of this territory to the expanding British colonies led inevitably to war and eventually the end of France's North American empire.
Frontenac was reinstated as governor in 1689, when nations of the Iroquois Confederacy were attacking New France. He had orders to seize the Iroquois supply base - the colony of New York. Instead, he sent raiding parties against frontier settlements there and in New England. As a riposte, a seaborne expedition under Sir William Phips besieged Québec. When summoned to surrender, Frontenac responded, "I have no reply ... other than from the mouths of my cannon and muskets." Sickness and cold weather forced the invaders to withdraw. Frontenac wrongly believed he could end Iroquois hostility with diplomacy. In 1696, under ministerial orders, he commanded a punitive expedition that destroyed Oneida and Onondaga villages and crops (see Iroquois Wars). Though less quarrelsome in his second administration, Frontenac still used his powers to profit from the fur trade, which he was accused of underwriting with military funds. Frontenac might have been dismissed had he not died in 1698.