In 1755, he led a group from the Three Fires confederacy in the defense of Fort Duquesne (later Pittsburgh), where the French and their Indian allies triumphed over the British Edward Braddock and colonist George Washington at the Battle of the Monongahela. Langlade also took part in the Siege of Fort William Henry. Later he led a group of Ottawa warriors at the Battle of the Plains of Abraham in the defense of Quebec.