The only child of the Maybe family and a relative of the wealthy Yess family (a family of trouser makers), he was a child genius and serial killer. (His middle name is Janet because his parents wanted a girl.) He deliberately kept his high intelligence secret, by learning to spell badly and act stupidly, in order to avoid getting caught. He killed for the first time at age 12, by murdering a neighborhood couple who he chose at random from the phone book, as an experiment. He moved on to gradually killing members of the Yess family, setting things up so his father could assume control of the company. After being captured by Judge Dredd, he was sent to an asylum.
After Necropolis , he escaped and fled back home (where he witnessed his parents' suicide). Shortly afterward, he was contacted by a family friend, Mrs Urchison. He killed both her and her only child, and used the family's face changing machine to alter his appearance to impersonate her son. After inheriting the family fortune and killing several more associates, he was apprehended by Dredd as he was escaping to Ciudad Barranquilla. By this time he had murdered 21 people before his eighteenth birthday.
Imprisoned for seven years in Iso-Block 666, he escaped again by drugging his psychiatrist and another patient with a mind-altering drug, to convince both of them that the hapless patient was in fact PJ Maybe. Using the Second Robot War as cover, he left the Iso-Block and attempted to change his face into that of a billionaire named Gunga Dinsdale. Tricked by a back street merchant (who disfigured him), he killed a street judge nearby and fled the city.
Once free, he stole the identity of Pedro Julio Montez and faked his own death. Maybe had his heart removed and replaced with an artificial one, the real heart being given to Judge Dredd as proof of death. The heart went on display in the Black Museum inside the Grand Hall of Justice. He later went back to Mega-City One to set up a lucrative business deal with the city. This was all subterfuge for his real plan: to kill six childhood tormentors for accusing him at age 6 of attempting to injure them (which he had done, but he felt that they should not have accused him anyway). After killing five of the six, he realised that Dredd might identify and protect the sixth, since Dredd now realised that Maybe was in fact alive. He therefore drugged a pilot and ordered him to crash into the sixth victim's apartment block, igniting an inferno that killed twenty thousand.
Shortly after his escape, several ambassadors from Mega City One came to Ciudad Barranquilla with Dredd guarding them - a cover for the Judge's secret attempts to locate him. Maybe was prepared for this, and murdered four ambassadors to taunt Dredd. He then kidnapped doctor and millionaire philanthropist Byron Ambrose and switched Ambrose's heart for an artificial one. After having his own DNA records swapped with those of Ambrose by drugged judges, he then tricked Dredd into believing he was dead by letting Ambrose die in a fire, to be identified as Maybe from the DNA and the heart, while Maybe assumed his identity. Maybe also had Ambrose's real heart swapped for his own in the Black Museum, and ordered the drugged judges to kill themselves, to avoid any possibility of his plans being discovered. He returned to Mega-City One, already planning more killings.
In 2129 Maybe was elected Mayor of Mega-City One after killing the mayor, running as a candidate in the ensuing election, and framing his opponent for the murder (and a string of other murders). While Maybe is now in a place of power (though given the status of the mayor's office, not very much), his murders led Dredd to suspect that once again Maybe has cheated death. By Christmas, he began killing for fun again (starting with the deputy mayor), though at the same time he has proven to be a highly effective civic leader, even gaining Dredd's approval.
In early 2130, a biography of his life was published; Maybe planned to kill the author. A young boy named JP Buwick began emulating PJ Maybe's early killings after reading the biography (including signing the killings "PJ Mabey"), and Maybe became paranoid that his identity was known and he was being challenged. He tracked down Buwick but was beaten to the punch by Judge Beeny, who was investigating Buwick's murders. Instead he killed the biography author by the same method he had intended to kill Buwick with: drowning her in a PortaPool of jelly which was then allowed to set, and left for the judges to find.
In 2132 Chief Judge Sinfield ordered Maybe to raise more revenue for the city, and threatened to undermine his re-election campaign if he did not comply. Maybe did not take kindly to these threats, and resolved to murder Sinfield instead.
To Maybe's extreme fury, two attempts involving infecting the Chief Judge with horrible (and normally fatal) diseases failed to kill Sinfield, and even worse inspired a wave of other people to attack the Chief Judge. Adamant that only he could kill the Chief Judge, Maybe stepped up his efforts, eventually sending a robot (disguised as former chief judge Hershey) to kill Sinfield. However Dredd destroyed the robot and saved Sinfield. Maybe's DNA was found on the remains of the robot, and because it matched Ambrose's DNA record, Maybe was arrested. Maybe successfully stood up to interrogation, but his true identity was finally discovered when Dredd compared his DNA to an old sample of Maybe's DNA from an archived evidence file pertaining to his earliest murders. When that DNA sample was found to match Ambrose's DNA record, instead of Maybe's, the record switch was found out, and Maybe finally confessed and was subsequently sentenced to death. The people were never informed of Ambrose's true identity, and they were told that the mayor had died of natural causes. Maybe later informed Dredd of his suspicions about Sinfield's drugging of Judge Francisco and helped him uncover the truth. As a result, his sentence was commuted to life imprisonment, although Dredd stated that he personly voted for Maybe to be executed.
Maybe escaped the following year, and remains at large. Over the next few months he managed to marry an wealthy but old woman and also executed a daring plan to murder his successer of the Illiberal Party (and leading candidate to replace Maybe as Mayor), as well as other candidates in the election. This occurred under the very noses of the Judges, though Dredd was lenient in their criticism, recalling the number of times Maybe had eluded him as well. During the events of Day of Chaos, PJ had to defend his wife's house from constant raids. When three of the Dark Judges turned up, Maybe managed to trick them into underestimating him and then trapped them in a wine bottle. They were rescued by Judge Death , who killed Maybe's wife. Maybe escaped, and remains at large.
- His M.O. usually involves face changing machines, drugs (mainly SLD 88 and SLD 89, which render people open to suggestion), and acting
- His personal assistant, accomplice and lover was a robot named Inga. PJ seemed to be in love with Inga, noting how much more reliable robots are than humans. She seemed to be the only thing he cares about, and while faking his death she was the only thing he retained, even though the almost unique robot could have led to people discovering his real identity. Inga occasionally killed people herself, and during Maybe's attempts to kill Sinfield she was happy to be allowed to participate. She was destroyed by Dredd while she was strangling the chief judge.
- Even following successful escapes, Maybe is incapable of stopping his spree or changing his M.O. significantly. This has twice led to him being caught by Dredd after successful escapes, and PJ was twice forced to fake his own death to escape Dredd's trail. He also seems unable to remain away from Mega-City One. At one point he had successfully taken control of billions of credits in Ciudad Barranquilla and faked his death well enough to satisfy Dredd, only to return to his home city a few years later and engage in a spree of murders that led Dredd to learn of his continued existence, track him down and force Maybe to fake his own death again, costing him his money and nearly his life.
- Maybe likes to "experiment" with his murders, for instance his creation of a robot device for use in his first murder. "Creative" killings like leaving copper skysurf pants for a skysurfer (who was then struck by lightning), drugging people into doing his killing for him, various unusual killings when he took revenge on a group of people who tormented him as a child (which made Dredd suspect his survival once again). Maybe rarely resorts to firearms, preferring his own methods of killing.
- Maybe had proved extremely capable at escaping capture, or escaping custody on those occasions when Dredd captures him. While his first escape from a psycho cube occurred in the fortunate chaos of the "Necropolis" disaster, he nonetheless successfully hid himself, took control of a large fortune, and remained hidden and safe for almost two years. While he was then held for more than seven years in a high security Iso-cube he bided his time and finally escaped shortly after the Robot war of 2121. On the run for more than a decade he escaped close calls with Dredd twice, before finally being captured after the Sinfield assassination attempts of 2132. A year later he escaped and has since eluded a massive manhunt.