Jonathan Joestar/History

Early Years
As an infant, his mother died in a carriage accident. That same accident indirectly brought Dio Brando into his life, because Dio's father unwittingly saved Jonathan's father while preparing to steal from the wrecked carriage. Twelve years later, Dario apparently died of illness and Dio went to the Joestars. Despite Jonathan trying to be friends with Dio, the latter would become his nemesis both as a childhood rival and as an undead enemy. At the young age of 12, when Dio came into his life, Jonathan met and fell in love with Erina Pendleton, but Dio shattered the relationship for a considerable time through his evil ways, by kissing Erina and boasting about it.

Stone Mask
Nonetheless, Jonathan is able to maintain his sanity and continues his studies in archaeology. Among his interests is research on a Mesoamerican stone mask that is part of the estate. Curiously, the mask sprouts spikes that pierce the wearer's skull if human blood touches it. Finally, after eight years, Jonathan takes a stand against Dio when he discovers that Dio poisoned his own father with a substance that imitated illness, and intends to poison George in the same way to take over the family fortune. Jonathan then travels to Ogre Street in order to find an antidote, which he locates thanks to the help of his new comrade Robert E.O. Speedwagon. In a fateful encounter, Dio stabs George while wearing the mask (having learned that the mask was not a killing device, but a means to let the wearer transcend humanity, mortality and anything resembling moral restraint to become a mighty vampire).

Battle with Dio
"We may have been two people making one, I even feel a bizarre friendship... And now our destinies have become one..."

- Jonathan Joestar to Dio before the ship's explosion

In the first confrontation with this new monster, Jonathan holds his own, but in his desperation to destroy Dio, he sets fire to the manor. In the battle, Jonathan, torn by the losses caused, grabs Dio and pulls him down many floors - ultimately impaling him on a goddess statue. Jonathan suffers horrible burns and is taken to hospital, whereas Dio is able to escape unseen. Robert E.O. Speedwagon finds out that the nurse taking care of Jonathan is actually Erina, who had gone to India after Dio disgraced her and ruined her relationship with Jonathan. However, Dio had apparently not extinguished her feelings for Jonathan. Shortly after being discharged from the hospital, Jonathan is taken in by Will Zeppeli, who teaches him Hamon in order to defeat Dio. He travels with Zeppeli and Speedwagon to the town of Windknights to confront Dio. On his quest, he faces many enemies such as Jack the Ripper and Bruford and Tarkus, and once again it appears that he has managed to kill Dio.

Marriage
Shortly after the Windknights battle, Jonathan and Erina marry and soon set sail for America on a honeymoon. Their trip is cut short by an attack courtesy of Dio (now only a severed head) and Jonathan makes the ultimate sacrifice, staying aboard the sinking ship in an attempt to take Dio down with him. Erina, though pregnant with Jonathan's child, escapes the shipwreck.

Legacy
One hundred years later, a coffin is dragged up from the ocean depths - inside of which is the Dio-Jonathan fusion resulting from Dio taking over the latter's body. Dio is shown in Part III to have survived the explosion and managed to remove Jonathan's head and merged his own with the rest of Jonathan's body, though the merge is incomplete until he absorbs Joseph's blood in his fight with Jotaro. Over the course of four years, using Jonathan's body, Dio impregnates an unnamed Japanese woman with a child that would become Giorno Giovanna, as well as other women with children who would become Donatello Versace, Ungaro, and Rykiel. He also pierces Jonathan's body with the Bow and Arrow, awakening Stands in Jonathan's descendants as well.

Steel Ball Run
Jonathan's counterpart in Part VII: Steel Ball Run is Johnny Joestar, formally named "Jonathan". Johnny's family also bears noble lineage, but makes its residence in America instead. Johnny's appearance and personality are very different from Jonathan's, however, possibly due to relatively little interaction with Dio.