When he was young, he was gentle, nice and utterly unlike his viciously criminal family. Pa Angel was not pleased by this, and kidnapped a surgeon from nearby Texas City to operate on him, making him the crazed cyborg he is now. He has a mechanical right arm and a steel dome over his skull with a dial on the front. This dial has four settings; from 1, where he's surly and disagreeable, all the way up to 4, which is when he is fully berserk. His favorite attack is a head-butt with his steel skull. He is not very bright at best and has often been outwitted.
Mean Machine's dial settings are:
On rare occasions, an extremely hard headbutt causes Mean Machine's dial to get stuck on 4½, which causes him to enter an Uncontrollable Butt Frenzy, where he can't stop headbutting.
He died during the Judge Child saga, but was brought back from the grave by the Judge Child to seek revenge on Judge Dredd. At the end of his return, he was captured by the Mega-City One judges and imprisoned. While there have been escapes and attempts to cure him, he is usually incarcerated in Iso-Cube 666 (which holds the most dangerous foes Dredd has gone up against and subsequently captured) in Mega-City One. He is also occasionally "loaned out" to the Judges for missions, such as when he was part of "The Three Amigos" alongside Judge Dredd and Judge Death.
He once married a competing Cursed Earth criminal named Seven-Pound Sally Suggs (named after the 7lb hammer she used when committing her crimes). This turned out to be a scam, as she easily tricked him into demonstrating his highest setting by ramming the side of the shack the Angels lived in, collapsing it on the rest of the Angels and allowing her to abscond with the loot the Angels had extorted from neighboring people as "wedding gifts". Mean Machine later discovered that she had born him a son, Junior, who is exactly as kind and gentle as Mean was during his childhood.
In Judge Dredd Megazine #218-20, Mean Machine received a cranial cybernetic implant called a Warden Device, which delivers extreme pain whenever he gets angry, so he could be released into society to marry Iso-cube visitor Porsha Wuss. Mean quickly shorted out the device and was reincarcerated.
Finally in 2129 (Prog 1536), the Judges succeeded in removing both his dial and claw, reverting him to his original simple and peaceful self. He has been released into the care of his son.
In a parallel universe, ruled by Judge Dread (an insane version of Judge Dredd), Mean Machine is one of Dread's lieutenants and has a fifth setting - Book a Plot in the Cemetery.
Mean appears in the Judge Dredd/Lobo crossover.
He was played in the 1995 movie by Christopher Adamson.
As well as appearing in Judge Dredd he has had his own eponymous series: