Mitch Shelley's life seemed to begin quite normally, he lived with his father, a well paid untouchable lawyer in the town of Viceroy, and their house keeper, Conchita Alverez (she was like a mother to Mitch). The first sign that anything other than the norm was at work was when Mitch began to have vivid dreams and visions of past times, of places and events for which he could have had no knowledge. Worried his father took him to all the best child psychologists, but to no avail. Conchita on the other hand considered that Mitch's dreams were memories of past lives and actually encouraged him to explore them. When his father found this out he was horrified, he fired Conchita and sent Mitch away to a boarding school where he hoped the body would have a normal education.

Mitch never forgave his father for separating him from Conchita. When he was old enough he went to university and studied law, eventually returning to Viceroy to compete with his father. Mitch set up a legal practice with his best friend, Richard Bessly, and married a girl called Paula. On the surface he was an up and coming legal eagle, but in truth he was working for the mob. He had a finger in very pot and knew the dirt and secrets on everybody. However Mitch Shelley was in way over his head and after a number of years decided to turn himself over to the police. With their nice life threatened Paula and Richard arranged for John Keach, a corrupt policeman, to kill Shelley. A bomb was planted in the legal firm's offices and Mitch Shelley was seemingly blown off the face of the Earth.

For most people that would have been the end of it all, but not for Shelley. His body became a test subject for an organization called the Lab. In their ongoing research to find ways to make people immortal they used what was left of Shelley and dozens of others and implanting them with highly-advanced nanotech machines called Tektites . For some reason Shelley was the only successful result and was resurrected with the surprising side effect that he gained a different superpower each time he was resurrected. The only other success was the insane project head, Hooker. The memories of his past life wiped Shelley escaped and went to ground as a homeless bum who had no knowledge of who or what he was.

For months Shelley laid low on the streets until he intervened to stop a drive by shooting and was gunned down. Waking minutes later to find himself still alive Shelley began to have flashbacks of his memories from Viceroy. Still unsure of who he was he started to head back to his home town, helping anybody that he could along the way. After dying and resurrecting a number of times he became something of an urban myth, the Resurrection Man, a guardian angel who would not die. Not wanting to loose their prize experiment the Lab sent out their own agents to capture Shelley including Hooker and assassins for hire, the Body Doubles.

Once in Viceroy he went to his old home only to discover his wife with Bessly. Knowing nothing of their involvement with his "first" death he initially trusted them. With Keach they tried a number of different ways to kill him, but he just kept resurrecting. Then Hooker arrived and all hell broke loose as Shelley regained his memories. Shelley knew that if he was truly to make a fresh start he would have to wrap-up all his former mob dealings and deeds. Working with private investigator Kim Rebecki he arranged for computer discs containing all the secrets of Viceroy to be passed to his crusading father and then arranged a shootout between most of enemies in Viceroy that left Bessly dead along with most of the mob.

With much of his past now severed Mitch, using money he had put away in his mob days, hired Rebecki to help him find the Lab that had used him as an experiment. As they worked together Shelley and Rebecki began to come close but they were interrupted by the arrival of Tommy Monaghan, the Hitman. He had been hired by Paula Shelley to kill her husband. After an initial battle Monaghan found that killing Shelley was easy, getting him to stay dead was something else. Eventually Monaghan agreed to help Shelley to find the right superpower to storm the Lab (be killing him over and over again until they found the right power). Once inside the Lab Shelley found himself battling Hooker again, their fight destabilized the Lab's nuclear reactors creating a nuclear explosion. However Shelley now had the answers that he was looking for and had destroyed the lab that had turned him into the Resurrection Man.

After helping Supergirl battle a creature called the Rider, Shelley was left in a persistent vegetative state, but the doctors would not let Rebecki turn off the live support so that he could resurrect. While in the coma he found himself in the Dreaming guided by the Phantom Stranger who professed to know Shelley from a previous life. With the help of the Stranger and Deadman he began to put together clues from his own memories and from evidence at the Lab. Somehow the being presently known as Mitch Shelley was actually an immortal who original could be killed and then would reincarnate, literally be born again as a baby, with a new superpower. However the last time he was reincarnated he was reborn as Mitch Shelley, the interference of the Lab and the infusion of Tektites only altered how he came back to life. How he resurrected rather than reincarnated. Still his memories from past lives were fuzzy, but he did remember one name, Vandal Savage.

Having resurrected with powerful quantum telekinesis powers Mitch found himself perused by a team from the DeWitt Corporation (the parent company of the Lab). After managing to defeat them he was surprised to be picked up by the Justice League of America. They had encountered Shelley in the 853rd century where he was a friend of a future incarnation of the League and they had decided to look him up when returning to the present. He found the League a little over powering and eventually left to peruse his own agenda. However before he left Batman had Oracle run a trace on the Lab and the DeWitt Corporation and uncovered a number of hidden installations.

Using the JLA information Shelley implanted himself into the Corporation with a number of cover identities slows destroying its facilities and resources as he searched for clues on his origin. He was uncovered by DeWitt, captured and subjected to a series of repeated killings and resurrections as the scientists tried to establish how the Tektites acted on Shelley. While being tested for pain tolerance Shelley made an unusual resurrection by coming back as a female. The scientists theorized that it was because females have a higher pain tolerance. While in that form Shelley managed to escape with the Body Doubles (who had been double crossed by DeWitt). In the depths of the DeWitt Corporation's labs Shelley began to discover the bigger picture.

His ancient enemy was Vandal Savage, a millennia old caveman who controlled and manipulated civilization with dictators since before recorded history. DeWitt was Savage's son and it was Savage's own Tektites that had served as the blueprint for the research at the Lab. Shelley also learned of another player, Immortal Man, another of Savage's enemies with the power to reincarnate after each death. The tentative conclusion was inescapable, was Mitch Shelley the missing Immortal Man? It was a theory that was shared by the Forgotten Heroes who counted Immortal Man as their leader. The freed Shelley from the Corporation and began comparing notes.

It was obvious that Savage was up to something larger than the DeWitt Corporation and research on his own Tektites. Cave Carson reasoned that Savage was trying to gain his hands on an incoming "temporal meteorite", a twin of the one that had originally given him and Immortal Man their immortality. Tracing Savage to Antarctica the Forgotten Heroes and Shelley prepared to launch an assault. The meteorite appeared directly on clue killing most of Savage's staff. The impact did not go unnoticed as the JLA, Titans and Young Justice sent teams to investigate. However all the heroes found themselves floored by the reality warping effects around the blast site. It soon became clear that a creature had landed with the meteorite. Savage found himself forced to aid Shelley against the creature.

Shelley confronted Savage over the work done by the lab, while Savage agreed that he was the source of the Tektites and that Shelley was his immortal enemy, he refuted the idea that Shelley was Immortal Man. It turned out that Savage had captured and imprison Immortal Man years ago. Whoever Shelley was originally or where he got his immortality was still a mystery. Forced by Shelley to release Immortal Man Savage agreed because they would need all their Tektites to battle the Warp Child.

As Shelley, Immortal Man and Savage neared the creature they realized that it had been sent by an unknown alien race. The aliens had first created the Tektites which arrived on Earth via the meteorite that had given Immortal Man and Vandal Savage their immortality. During the battle with the Warp Child Immortal Man merged his Tektite field with that of the Warp Child and then by force of will over loaded his Tektites setting up a chain reaction that destroyed the Warp Child and himself, Tektites and all. In the aftermath Shelley was hailed a hero, but chose to return to Viceroy and his new found romance with Rebecki.

Over the following millennia the Resurrection Man and Vandal Savage would clash time and time again with Shelley taking over from Immortal Man as Savage's chief opponent. Alongside Supermen or utterly along, in the shadow of exploding stars or on the shores of alien seas, hidden in primitive societies or in full view of the Headnet Savage and Shelley danced a bitter dance across the stars. It was Savage who killed Shelley's daughter on the streets of Beijing and for a brief few hours they almost became friends. By the 853rd century Shelley had mostly withdrawn from public life and had become the tactical advisor to the Justice Legions.