Miles Warren was born into a family with a proclivity for science. His brother became a science teacher at Midtown High School where Peter Parker was his favorite pupil, but Miles' talents far exceeded that. After earning his Ph.D in biochemistry, Miles traveled to Wundagore Mountain to assist the High Evolutionary in his experiments to evolve animals into human form. Whereas the Evolutionary's subjects never fully lost their animal appearance, Miles succeeded in creating two "New Men" who looked practically human. This caused some friction between Miles and the Evolutionary that accelerated when a group of New Men began to worship Miles. When Miles evolved a jackal that exhibited a Jekyll-Hyde personality and then escaped, the Evolutionary banished him from Wundagore. Miles stayed in the area where he met and married Monica, fathering two children, but he spent so much time with his research that Monica took the children and left. Unbeknownst to the Warrens, Miles' jackal-man, envious of his creator's life, had been stalking the family. He caused a car accident that killed Monica and the children. When Miles learned of this, he realized the cause and blamed the High Evolutionary. He returned to Wundagore, challenged the Evolutionary and left with the New Men faction that worshipped him, promising to make them human.
He returned every summer but spent the rest of the year in Manhattan where he had obtained a position as Professor at Empire State University. There, his brother introduced him to Peter Parker on the same day that Miles first saw and immediately fell in love with Gwen Stacy. Disturbed by his feelings, Miles convinced himself his intentions were paternal and that Gwen was like the daughter he never had, blotting out the memory of his dead children. The following semester, both Peter and Gwen were students in his biology class. Continuing his New Men research, Miles hired Anthony Serba as an assistant and had him collect cell samples from the students in his class. He created a serum from these samples and injected New Men volunteers. The serum made the New Men human but transformed them into living corpses, then killed them. Miles tried to genetically engineer duplicate bodies for the New Men, making his first excursions into cloning which he later continued at ESU with Serba. Back in New York, Miles invited Peter, his best, though occasionally distracted, student, to a science demonstration. When Peter brought Gwen Stacy along, Miles couldn't help but voice his approval. When Spider-Man appeared, Miles expressed an interest in studying him.
To Peter Parker, Miles was a professor who badgered him about not attending classes. Even after Gwen Stacy was killed by the Green Goblin (Norman Osborn, also apparently killed), Miles kept up this routine but inside he was devastated. The day after Gwen's death, Serba showed him a frog produced by their cloning experiment. Miles then gave Serba tissue samples from Gwen and Peter. When Serba discovered he was cloning humans, he came to Miles and demanded their destruction. Hushing Serba up, Miles accidentally killed him. Unhinged by his act, he became convinced someone else did the murder. When he walked past a class discussing jackals, he recalled his jackal-man and created an evil alter-ego for himself: the Jackal. He designed a green costume with electro-prod claws and began extensive athletic training. Believing Spider-Man was responsible for Gwen's death, Miles sought revenge but his evil side also yearned to be a crime boss. So, the Jackal convinced the Punisher to kill the web-slinger. He then murdered the Punisher's colleague, the Mechanic, hoping to blame the Punisher for the crime. When this failed, he arranged to bring Hammerhead, Dr. Octopus and Spider-Man together, hoping to pick up the gangland pieces, but this scheme also fizzled.
Meanwhile, Miles' clones were not developing properly, degenerating quickly into genetic waste. He hired a new assistant, Seward Trainer, and put his clones in stasis. The Jackal began spying on Peter Parker in search of a link to Spider-Man. He spotted Peter tossing a web-bundle on his apartment building roof, which contained a spare Spider-Man costume and web-shooters. Stealing this, the Jackal was almost certain Parker was Spider-Man but he wanted absolute proof. He hired the Grizzly to lure Peter into a trap. He then attached a metal harness to Peter's arm, telling him the device was a homing beacon that would explode if removed. This was a ruse to induce Peter to go to the ESU labs where he disposed of the harness. Peter then changed to Spider-Man with Miles secretly watching, confirming his suspicions.
During this time, Norman Osborn, still alive, had established himself as a criminal mastermind in Europe, leading the cabal called the Scriers. He stepped in to help Miles' cloning, via his Scrier representative. The Scrier caught Seward Trainer stealing secrets and demanded a future favor in exchange for his silence. Together, Miles, Seward and the Scrier birthed the first successful Peter Parker clone. However, the clone began to exhibit cellular degeneration. Learning this, Miles planned to kill his flawed creation but the clone escaped, later calling himself Kaine. Other failed Parker clones followed until Miles refined his technique and somehow created stable Peter Parker and Gwen Stacy clones as well as clones of himself. Miles briefly returned to his New Men, this time in his costumed identity, inspiring the Cult of the Jackal. He vowed to fulfill his promises but never returned. Back home, he used drugs and hypnosis to bend the new clones to his will, then began tormenting Spider-Man by sending the Gwen clone to Peter Parker's apartment.
Before continuing his plans, Miles combined his cells with his genetic virus to create a clone intended to destroy the human race, but the creature awakened too early to have full powers and became Carrion. Eventually, with Tarantula (Anton Miguel Rodriguez) in his employ, Jackal revealed his identity to Spider-Man, then pitted him against his Spider-Clone in a fight ending in an explosion that seemed to kill both Miles and his creation. In reality, the killed Jackal was a clone. Miles stepped out of hiding, found both Spider-Men alive and injected what he believed was the real one with a drug to simulate death. His plan was to later retrieve the body, revive him, and brainwash him into thinking he was the clone. Convinced by this, the "real" Spider-Man took the name Ben Reilly and left the city.
In reality, Miles' tests had been manipulated by Seward Trainer, following Norman Osborn's secret agenda, and Ben Reilly was the clone. Miles moved to a lab in upstate New York where he spent five years in a genetic regeneration chamber, reshaping his body to resemble his jackal-man, creating clones by long-distance and going totally insane. The High Evolutionary, thinking the Jackal dead, forced his Cult into hiding, then forged and planted a diary in Miles' handwriting to discredit his clone work by claiming the Parker and Gwen clones were Serba and a woman named Joyce Delany, who had been genetically reconstructed by the same genetic virus Miles previously tried on the New Men. The Evolutionary also planted Miles' genetic virus, which turned student Malcolm McBride into another Carrion. Believing all this, the superbeing Daydreamer transformed the Gwen clone into Joyce but she reverted back, later meeting and marrying Warren Miles, a Professor Warren clone who eventually degenerated.
As Miles' regeneration approached its completion, he summoned Ben Reilly, now known as the Scarlet Spider, and Peter Parker to his lab where he tormented them with clues about their true identities and subjected them to clones, which degenerated rapidly, even revealing a third Peter Parker whom he claimed was truly the original. His real goal was to get inside Ravencroft Institute to steal a sample of his Carrion Virus contained within the body of the villain Shriek. While Seward Trainer's switch resulted in tests proving Ben Reilly was the real Spider-Man, Miles teamed up with the third Parker, who was a combination clone/genetic construct he named Spidercide, to unleash his improved Carrion Virus on Springville, Pennsylvania, killing nearly everyone in town, a first step toward killing the entire human race and replacing it with clones. The Jackal planned to set off his next virus bomb at the Daily Bugle but faced opposition from Spider-Man, the Scarlet Spider, Mary Jane Watson-Parker and the Gwen Stacy clone. When Gwen fell off the roof, Miles' love resurfaced and he attempted to save her but fell to his own death instead. Unless, that is, he was only another clone.
An alleged son of Miles Warren became the new Jackal but was quickly defeated by Beta Flight.