Jaylah was a female survivor of an attack by Krall. For years, she lived in the crashed hulk of the starship USS Franklin on the planet Altamid. In 2263, Jaylah helped the crew of the USS Enterprise, after it was destroyed, to fight and defeat Krall, leaving Altamid in the process.

Years prior to her encounter with the USS Enterprise crew, Jaylah and her family, like many before them, were attacked by Krall and imprisoned on Altamid. Jaylah and her family quickly realized that people were routinely taken from Krall's holding cells and killed, so they decided to attempt escape. During the attempt, Jaylah and her father were confronted by Krall's subordinate Manas. Jaylah's father stayed behind to hold off Manas, buying Jaylah time to flee at the cost of his own life.

Jaylah discovered the derelict hulk of the Freedom-class USS Franklin and made her home in it. She hid it using holographic technology and set up multiple defensive traps in the surrounding area. Inside the vessel, she discovered a music player, and found she particularly liked music which featured "beats and shouting". She also learned how to speak English from the ship's records. In time, Jaylah became a formidable warrior, skilled in martial arts and in wielding a quarterstaff that doubled as a rifle.