|“||I don't care about 'living' or 'dying' or who's 'just' and who's 'evil'!! I don't even give a shit about the 'Corpse' being a Saint or whatever!! I'm still 'negative'! I want to get up to 'zero'! If I can get the 'Corpse' I can get my 'negative' back to 'zero'!||”|
Johnny Joestar is a depressive ex-jockey, who clings to his hope of regaining the use of his legs through the Spin and then the Corpse Part throughout Steel Ball Run.
Johnny is introduced as a distant paraplegic man, whose career was ruined when he was shot in the spine after conceitedly antagonizing a passerby. After Johnny witnesses Gyro's Steel Balls and Spin, and how they enabled him to stand up on his feet for a moment, he becomes determined to follow him and make him teach the Spin, then after discovering the Corpse Part making his legs twitch, to acquire them.Johnny stubbornly follows his intentions of following Gyro then track the Corpse. Disregarding the risks or the consequences, Johnny focuses on his goal and puts it above anything else. Several times Johnny endured severe wounds in order to reach his goals, notably trying to get on his horse Slow Dancer which earned him many bruises and a wooden shard through the leg; despite his repeated failures his determination at participating in the race didn't waver. Inversely, Johnny has no qualm being violent or killing his opponents to get the Corpse Parts. Gyro Zeppeli has mentioned that Johnny had "dark determination" in his eyes indicating a ruthlessness which would make Johnny able to kill in cold-blood. This obsession with the Corpse almost trumped his friendship with Gyro and Johnny almost let him die in order to keep the Corpse Parts. This amoral selfishness still extends to the interest of his loved ones and followed him during his whole life, demonstrated years after the Steel Ball Run, as when his wife Rina was struck with the Rock Disease, Johnny then stole the Corpse to beg it to transfer the disease away from her, not caring who would receive it and suffer in her stead. Yet Johnny isn't completely amoral, for instance objecting to involve the defenceless Lucy Steel in their struggle for the Corpse and ultimately taking the Rock Disease for himself to save his son.
During Steel Ball Run, Johnny was burdened by depression and a subsequent lack of confidence. Notably calling himself a useless person, Johnny's bleak outlook of life stemmed from his youth. During his childhood, Johnny was a timid yet kind child, adopting a wild mouse and calling it Danny. Though he was afraid of his harsh father George Joestar, he would try to live up to his expectations. Johnny idolised his older brother Nicholas but when he died, falling from a horse which was seemingly startled by Danny, Johnny became guilt-ridden, believing that his brother's death was his own fault and that he should have died instead. He then believed throughout the years that Fate itself was taking revenge on him for his crime and that every misfortune he received was in fact deserved. It resulted in his obsession with the blessing of the Corpse which would reset his karma to a neutral state of "zero" as opposed to the "negative" state of his curse. It also explains Johnny's rampant lack of confidence and near constant bouts of panic as he thought that Fate could at any moment take away his hope of acquiring the Corpse. In addition, when his father disowned him, Johnny, shocked, shut himself off, creating a facade of conceitedness to hide the sadness this rejection caused him.
Johnny's perspective improved greatly upon meeting Gyro Zeppeli. Having met someone who gave him hope and was genuinely nice to him, Johnny felt grateful for meeting the Italian executioner and treasured this relationship, at one point willing to abandon the Corpse Parts he had to save his friend. Gyro repeatedly knocked Johnny out of his lack of confidence and helped him get the Corpse Parts, giving him assurance and optimism in life. As reflected in the multiple ACTs of his Stand Tusk, the improvement was gradual, the key steps of his progress being Johnny discovering the Corpse (ACT 1), then standing up for himself against Soundman (ACT 2), symbolically cleansing himself of his guilts against Axl Ro and being blessed by Jesus-Christ's apparition (ACT 3) and finally acquiring the Corpse and regaining the use of his legs (ACT 4) Although Gyro died, Johnny kept a good memory of everything that happened. If during the race, Johnny was uncaring of everyone else save himself and Gyro, only maintaining a polite but cold demeanour at best toward the people he met, Gyro's influence made Johnny slightly more friendly toward people, culminating in his marriage with Rina Higashikata.
In JoJolion, a flashback shows that Johnny maintained that happiness during his life with Rina.
He chose to make Johnny and Gyro around the same age so they could be less formal and more friendly than their original counterparts similar to the Joseph-Caesar relationship from Battle Tendency. Gyro's random jokes and Johnny's use of his spinning nails to accomplish trivial tasks were included to reflect this concept.
- George Joestar I: Johnny had a complex relationship with his father. In one hand Johnny always sought his father's affection and approval. On the other hand, when George wondered if "God had taken the wrong son", Johnny was deeply saddened and chose to abandon his love for his father, shutting his heart. Johnny confessed to Valentine that he could not think of his own father in the same admiring way Valentine thought of his. Towards the end of the Steel Ball Run race, however, George shows up in the crowd and shows Johnny Nicholas' boots, reconciling with his son at last. Johnny named his son after George.
- Nicholas Joestar: As his elder brother, Nicholas was a model to follow. Johnny admired him since his childhood and feels excessively guilty over his death, thinking that the Universe cursed him for it.
- Danny: While Jonathan and Danny the dog had a shared childhood, this mouse was only a temporary pet for Johnny. When Nicholas died, Johnny believed that Danny and thus him, were responsible for frightening the horse Nicholas was riding and causing his death. Johnny retains good memories of the mouse but also haunting ones, even summoning it when Civil War affects him.
- Rina Higashikata : Johnny and Rina's relationship began after the race and persisted for several years. Both fell in love with each other soon after meeting and they became married, livng a happy life for a while. After she becomes ill, Johnny goes searching for the corpse parts as a cure. His love for Rina is so deep, he ends up sacrificing himself to save her and their son.
- George Joestar II: Johnny loved his son deeply. When the Rock Disease bounced into him, Johnny sacrificed himself to save George and confided that he was happy to have him in his life.
- Gyro Zeppeli: Johnny and Gyro are friends, partners in the Steel Ball Run and also apprentice and master in the art of the Spin. At first Johnny's determination got Gyro's interest, causing him to help him figuring out how to mount his Slow Dancer and start the race. After the first stage, Johnny wins the respect of Gyro, thus Gyro decides to teach him the Spin and they become partners for the rest of the race. As the stages progress their friendship grows. Despite their opposing personalities, causing regular clashes as to how to take on a difficult situation, Gyro and Johnny ultimately get along well and share many moments of friendship such as telling each other a secret. Gyro notably likes to jest with Johnny and tells him bad jokes or miscellaneous songs that Johnny appreciate. Due to their regular battles, Johnny and Gyro fight well together, and see each other as valuable allies. Their friendship is such that any one is ready to put himself in danger for the other, and Johnny notably abandoned his Corpse Parts to save Gyro's life. When Gyro died, Johnny was devastated and Valentine exploited that bond to promise Johnny that another Gyro would walk this universe. Gyro's ghost salutes Johnny one last time and the latter would bring back his corpse to the Zeppeli family. Gyro's continuous support helped Johnny get out of his depression and enabled him to begin anew. The relationship of the two has similarities of Jonathan's relationship with Will or Joseph's relationship with Caesar.
- Lucy Steel: Johnny and Lucy are allies against Valentine, but do not interact with each other much. Despite being Jonathan and Erina's counterpart, they never develop a relationship.
- Mountain Tim: Mountain Tim was first suspicious of Johnny as Benjamin Boom Boom tricked him into believing Johnny was killing competitors in the race, but both later became allies in the fight against the Boom Boom Family and Oyecomova. Tim notably taught Johnny about the Devil's Palm and Stands.
- Diego Brando: Johnny considers Diego a rival in his quest for the Corpse Parts. Due to Diego's own ruthlessness, Johnny won't hesitate to kill him if he gets in his way. At one point, Diego allies with Valentine to kill Johnny and Gyro, but it doesn't last. While their relationship is more positive than that of their counterparts, Jonathan and Dio, they are enemies all the same.
- Hot Pants: Johnny considers Hot Pants a rival in his quest for the Corpse Parts. He realizes that she is a woman after Gyro kills Ringo Roadagain, but doesn't reveal her true gender to Gyro out of respect for her privacy. After Hot Pants steals Johnny's Corpse Part yet leaves him a small part of the Spine, he is curious about Hot Pants motivations for acquiring it.
- Sandman: Because Sandman didn't go after the Saint's Corpse and acted friendly with the duo, Johnny didn't see him as an enemy. Ultimately, Sandman allied with Valentine and tried to kill Johnny with Gyro and take the Corpse Parts, they thus became enemies. Still, Sandman was indifferent to Johnny, only seeing an internal struggle among the white men he considered enemies that he could exploit.
- Funny Valentine: As both tried to gather the Saint's Corpse, Johnny and Valentine were enemies, but didn't interact much until their one fight. Because of his selfish motive, Valentine saw Johnny as unworthy of the Corpse and tried to kill him, nonetheless, Valentine threaded carefully with Johnny since Tusk was partly immune to his Dirty Deeds Done Dirt Cheap.
- Diego Brando from Another Universe: Johnny and this version of Diego both tried to take the Saint's Corpse, they were enemies. Diego was wary of Tusk, which could move partially in the stopped time, and likewise, Johnny learned of THE WORLD's power and also was wary of it.
- Dr. Ferdinand: Ferdinand was one of many assassins sent by Valentine to kill him. Ferdinand attempted to transform him and Gyro into dinosaurs. After a tough battle, Johnny and Gyro defeat Ferdinand.