Birtwistle was the coxswain aboard Edward Kenway's ship, the Jackdaw.


Upon the ship's return to Bristol in 1723, Edward planned to assassinate the Templars responsible for an attack on his family a decade earlier. Having learned that a troop of soldiers were on their way to Bristol, Edward met with Birtwistle in a tavern. There, he instructed the coxswain to bring the Jackdaw to the harbor, in preparation for their escape from Bristol.

As Edward was about to kill Matthew Hague, the target's father Aubrey arrived, accompanied by British First Lord of the Treasury, Robert Walpole. Walpole proclaimed Matthew's relative innocence, and offered Edward and his crew pardons in exchange for the survival of Matthew. Wanting the best for his family and crew, Edward accepted, allowing Birtwistle to begin a new life.