- "John de la Tour is brash, he draws too much attention to himself, I thought he would surely compromise the Brotherhood. But I was wrong. He misdirects with charm, he hides in plain sight behind a smile. The people know that he is rich and that he is dangerous, but they never get a moment to question why. Still, he is unbelievably arrogant. I like him, but I don't trust him. I wonder if we will be able to work together."
- ―Achilles Davenport voicing his opinion of John.[src]
A member of a wealthy family, John de la Tour resided in Acadia, and operated under direct order of the French Assassin Council. In 1740, he became acquainted with Achilles Davenport, who had been sent to the Colonies by the Mentor of the Caribbean Brotherhood, Ah Tabai, in order to establish a new Brotherhood. Upon first meeting de la Tour, Achilles learned that he had attempted to build a network for gathering information, with the intention of easily identifying any potential threats aimed towards the colonies, and personally theorized that the New World contained several First Civilization sites and artifacts. Achilles did not hold de la Tour in high regard, believing him arrogant.
In 1744, John accompanied Achilles to Quebec in order to locate Mathieu Léveillé, a slave from Martinique who had been believed to possess certain knowledge regarding the First Civilization. However, due to the weather conditions, the two were delayed on their journey, and by the time of their arrival, Mathieu had passed away from an unknown illness in September 1743.
Fortunately for the Assassins, they discovered that the government had arranged a marriage between Léveillé and Angélique-Denise. However, the ceremony never took place, and the woman was put up for sale at a slave auction. Acting on impulse, de la Tour bought her, but not before Mathieu was able to share his secrets with her. Witnessing this act changed Achilles' view of John, whom the former came to respect.
In 1745, John journeyed to Louisbourg, with Achilles and Angélique posing as his slaves, in search of a safe house owned by Nicolas Court, a Hermeticist who studied the mythology of the indigenous people of the New World. De la Tour believed that Nicolas held valuable information that would lead them to finding First Civilization Temples. With the pair posing as slaves allowing them the benefit of drawing less suspicion and moving easily through the city, Achilles was nevertheless irritated by the charade, contrary to John.
However, as the conflicts between European powers had reached America, British troops appeared in the city. John and Achilles attempted to enlist the aid of the French government, but were turned away as the French decided to reclaim their lost territory through treaties and negotiations, a tactic which the Assassins were skeptical about. De la Tour and Achilles helped prepare the Louisbourg fortress for the impending British attack, while Angélique searched the city for the safe house.
When the conflict between the French and the British finally erupted in the colonies, de la Tour realized the Templars would attempt to take advantage of it for their own purposes. John presented Achilles with his Assassin robes and named him as Mentor of the Colonial Brotherhood, before leaving to fight against the invading British forces, in order to buy Achilles and Angélique time to complete their mission, ultimately sacrificing himself in the process.
Thanks to John's sacrifice at Louisbourg, Achilles survived the battle and one year later officially founded the Colonial Brotherhood of Assassins, based at Davenport Homestead in Massachusetts, becoming its first Mentor.
- De la Tour meaning "of the Tower" in French.
- John sharing his surname with Charles de Saint-Étienne de la Tour, a governor of French Acadia during the 17th century. It is unknown if the two are related.
- Achilles once referred to de la Tour as «the first Assassin to come to the colonies».
- In Assassin's Creed III: Liberation, stores with the name "De La Tour" can be found.