Penelope Young was a student of Gotham University where she graduated with top honors and was later hired as the head of the Arkham Asylum research department by Warden Quincy Sharp in an effort to restore the sanity of various super-villains of Gotham City. She earned a reputation for being focused on and dedicated to her career, willing to take whatever actions were necessary to advance in her profession and being intolerant of those who got in the way of her work.
At her post as head of the Arkham research department Young devised Project Titan, a project to create a chemical called titan that could be used to strengthen weak asylum inmates so that they could undergo the more intense methods of treatment. A Mr. Jack White gave Young funding for the project and also backed the transfer of Bane (who was transferred under the alias 'Patient X') from Blackgate Prison to Arkham Asylum so that Young could use venom from his body as a compound for the titan formula. Young used plant-based hybrids in Arkham's botanical gardens to create the first version of the formula and tested it on a Blackgate prisoner, however this resulted in a dangerous and extreme mutation of the prisoner into a monstrous creature.
Young had conducted a number of interviews with patients under the treatment of the asylum and decided the Joker would be the perfect candidate for Project Titan. In a subsequent interview she discovered Jack White was an alias the Joker had invented and that the Gotham City Police Department believe Bane had escaped. Upon discovering this Young returned all funding she had received for Project Titan to the Joker and refused any more financial backing from him. The Joker allowed himself to be captured by Batman so that he would be returned to the asylum where he could start a riot and finish project titan himself, creating an army of titan-fueled monsters for his own amusement.
Young appeared visibly nervous around the Joker as he was returned to the asylum despite her actually being in little direct danger. After the Joker initiated his prison riot he demanded that Young aid him with Project Titan. While Young was carrying out her normal duties in the x-ray room of the medical facility the area was raided by Joker's henchmen, led by Harley Quinn, who shot the security guards and captured a number of doctors, including Young, who they trapped in a locked office to interrogate. Batman managed to use explosive materials to incapacitate the thugs holding Young in the office without her being harmed.
Almost immediately after being saved, Young headed to Arkham Mansion with security guard Aaron Cash protecting her, unknown to Batman. She was attempting to retrieve the titan formula notes to stop Joker acquiring them, however Batman soon learned of this and went after Young. The Joker's henchmen took Aaron Cash prisoner but despite the pursuit of Joker's men Young managed to enter her office, retrieve her notes and escape to the lower level of the mansion library which was being guarded by two security personnel and where there were two guards within, one of them named Bill. The Joker's henchmen killed the two guards at the entrance and Young managed to hide her notes shortly before they overpowered Bill and captured him, Young and the other guard.
Young was taken to the Joker who was dissatisfied with the absence of her notes and ordered Zsasz to torture the necessary information about the titan project out of her. Batman found and destroyed Young's notes on project titan and when he finally reached Young, Zsasz ordered him not to come any closer, threatening to hurt Young, however Batman managed to knock Zsasz out without harming Young by using a batarang. Young then opened a safe in the Warden's office, trying to obtain a key to a titan production lab in the botanical gardens but found the safe has been rigged with a bomb and died in the explosion.
In the last of the hallucinations Batman had in the game (which are induced by Scarecrow's fear gas) Batman sees Young again, as one of the prisoners of the asylum. Eventually Batman manages to shut down Joker's expansion of Young's Titan Project.
In Batman: Arkham Asylum Young is voiced by Cree Summer.