During her father's travels in the Caribbean, Jennifer lived with her mother in Wales. Born after her father's departure, Jennifer was unknown to Edward, but following the death of her mother in 1720, made arrangements to travel to Great Inagua to be with him.
Returning to England, Jennifer soon came to live with her father, his second wife Tessa Stephenson-Oakley and their son Haytham in Queen Anne's Square in Bloomsbury, London. However, she refused to use the Kenway surname, saying that she had been raised solely by her mother in her early years and would thusly keep her mother's maiden name.
She was renowned by the noblemen of London for her great beauty, and for her "smokey" stare, though Haytham thought of it to be more akin to a scowl, due in part to her resentment of her father for not training her in the ways of the Assassins. As a result, she was often cold towards her half-brother, and railed against her father's plans to marry her to Reginald Birch, one of the Kenway's senior property managers.
After discovering Birch was a Templar and informing her father, five mercenaries kidnapped her after storming the house, killing her father and taking his journal. Birch had her sold to Turkish slavers, while pinning the crime on Edward's valet Jack Digweed and taking Haytham under his wing.
Jennifer became a concubine in Topkapı Palace, and by 1757, she was transported to Damascus, to serve under the Ottoman governor in charge, As'ad Pasha al-Azm. However, since Jennifer was in her mid-40s at the time, she was too old to be a concubine, working instead as a servant. Ultimately, Haytham and his loyal friend, Jim Holden, infiltrated the palace to find and rescue her.
After informing Haytham that Birch killed their father, they launched an attack on his chateau near Troyes, France. Jennifer attacked Birch in his office, and despite him holding a knife to her throat, she managed to throw him onto a sword pinned in the door, ending his life.
She returned to London to take hold of the mansion in Queen Anne's Square, and while she and Haytham stayed in touch, their correspondence was distant since neither of them knew each other very well. Jennifer was also somewhat disappointed that her half-brother opted to remain a Templar after dealing with Birch.