Born in Quebec, Gibault was ordained in 1768 and soon took up a mission in present-day Indiana. When the Virginia militia under Colonel George Rogers Clark entered the area during the War of Independence, Gibault and others met the American commander and pledged the support of the region to the Americans in return for assurances of religious freedom. Against the wishes of the bishop of Quebec, Gibault led the French residents of the Vincennes region in cooperating with the revolutionaries.