Jotaro Kujo is initially seen in the series willingly having himself imprisoned, believing himself to be possessed by an evil spirit. This leads to his mother, Holly Kujo, contacting Jotaro's grandfather, Joseph Joestar, to visit Japan and make Jotaro leave his prison cell. Although he originally refused to leave prison, to the point of ripping off Joseph's prosthetic finger and shooting himself at a point-blank distance with a handgun only to be saved by Star Platinum, Jotaro complies after Joseph and his friend, Muhammad Avdol, explains to him that an evil spirit was not possessing him and it was only his Stand manifesting from him.
Joseph explains that the old enemy of Joestar's family, who is a vampire over 100 years old named Dio Brando returns to the civilized world. According to Joseph, his own grandfather Jonathan Joestar fights with Dio 100 years ago on a ship while traveling across the ocean. This fight finally ends up with the ship explodes, but Dio survived the explosion by merging his head with Jonathan's dead body and hid in a coffin. This coffin sank into the bottom of the ocean, and Dio sleeps in the coffin while absorbing Jonathan's life energy for around 100 years. But this coffin was accidentally discovered by a pass-by ship and dug out from the bottom of the ocean and eventually, Dio returns.
Jotaro Kujo finds out what he thought as an evil spirit was actually his "stand". Stands are entities generated from people's life energy, each stand has a unique superpower, and people who have abilities to summon stands were called "Stand Users". Jotaro Kujo's stand is named Star Platinum, it appears like a strong, muscular man with long, flowing hair and purple skin. Its facial features are similar to Jotaro Kujo.
As a Stand User, Jotaro Kujo can summon Star Platinum whenever he wants or hides it in his body. Star Platinum is a close-range Stand, so it stays about 2 meters from Jotaro's body after being summoned and seems always floating above the ground. The power of Star Platinum is incredible strength, speed, and precision. Jotaro Kujo also discovered many uses for his stand.
Also, Jotaro Kujo can do incredible things with his stand, Star Platinum shares a similar state with Jotaro Kujo. If Jotaro Kujo gets hurt, Star Platinum will be hurt in the same way, and vice versa. Fortunately, a stand can only be affected or hurt by another stand. Normal people even cannot see stands.
- Strength: Star Platinum possesses incredible strength, it was stated to be one of the most powerful stands. Star Platinum used to throw a Jeep with one hand, break a prison cell, and cracked several giant teeth hard as diamonds within seconds.
- Speed: Star Platinum can make moves extremely fast. It can catch bullets in nearly close face distances, can throw powerful punches with incredible speed that created mutiple afterimages, and is stated to be faster than light in comics.
- Sight: Star Platinum has extremely strong eyesight. It once saw a tiny fly appeared in a photo and drawed its whole body with complete details.
- Phase: As an entity generated from life energy, Star Platinum can be untouchable if Jotaro wants. Then it can phase throw people's bodies to affect their inner organs. This phase ability is also effective to Jotaro himself, once used this ability to stop heartbeat for a while by commanding Star Platinum to grab his heart.
- Star Finger: Star Platinum's long-range attack. Jotaro needs to relax his body to concentrate power on Star Platinum's finger, then it can extend its middle and index fingers to a range of a maximum of two meters to stab opponents afar.
- Time Stop: After fights with his enemy Dio Brando, Jotaro finds out his stand is a similar type stand to Dio's stand "The World". Thus Star Platinum awakes the ability to stop time for maximum 5 seconds, a similar ability to The World. When Jotaro stops the time, only himself can move in the frozen world and interacting with other objects.
Fight with Dio
After a long trip from Japan to Egypt and defeats several Stand Users who are Dio's subordinates, Jotaro finally meats Dio. Dio has a Stand named The World. This Stand is incredibly strong and fast, just like Star Platinum. However, The World can stop time for several seconds, which makes Dio the most dangerous enemy so far. Jotaro finds out that he can sense the frozen world during Time Stop, and he can move for approximately 1-2 seconds. Jotaro realizes Star Platinum can also affect time somehow, this might be because The World and Star Platinum are similar types Stands. He then learns Dio's Time Stop power, and stop time while Dio is not noticed. Finally, Jotaro punches "The World" with all his strength-focused into one hit, this attack cracked "The World" into pieces, and those wounds reflected on Dio's body. After putting Dio's body under sunlight, Dio's body burns into ashes and died properly.
Diamond is Unbreakable
In the fourth part of JoJo's Bizarre Adventures, Jotaro Kujo grows older and wears a white suit. He travels to the town of Morioh to search his grandfather Joseph Joestar's illegitimate child Josuke Higashikata. He finds out that his younger uncle Josuke is still in high school. Josuke also gains a Stand named Crazy Diamond, this Stand has the power to fix broken things. Jotaro nearly involves in a fight with Josuke during their first formal meet because of some misunderstandings. This situation forces Jotaro to use his Time Stop power which he hasn't used for a long time. According to Jotaro's description, if he didn't stop time, this fight might end up both getting hurt severely. After then, Josuke becomes Jotaro's trustful ally. At the same time, a mysterious killer appears in the town, Jotaro decides to find this killer with help from Josuke and Josuke's friends.
In the year 2011, Jotaro Kujo's daughter Jolyne Cujoh is being set up in jail for 15 years imprisonment. Jotaro sends an amulet with a piece of a Stand Arrow inside to Jolyne. Jolyne accidentally gets penetrated by the piece and awakes her Stand Stone Free. She finds out her stand power is to transform her body or parts of her body into threads. A few days later, Jotaro himself goes to this jail to help Jolyne escape. Jotaro appears as a tall adult man wearing a purple suit. Right after he meets Jolyne, a mysterious Stand Manhattan Transfer starts its attack. Jotaro finds out there is another Stand sneaking around them, but in order to save Jolyne, Jotaro was directly hit by this Stand Whitesnake. Jotaro's Stand and mind were transformed into two DISCs and taken by Whitesnake. Under this effect, Jotaro becomes nearly PVS. The only way to save Jotaro is to take back the two DISCs and insert them into Jotaro's body again. Saving her father's life becomes a difficult task for Jolyne.
Fall of the star
Jotaro eventually recovers from the coma after Jolyne sends back DISCs and SPW inserts them into Jotaro's head again. He surprisingly appears and saves his daughter from bullets in the middle of a fight between Jolyne and Enrico Pucci, the man behind all those schemes. Jotaro throws a punch to Pucci's face but accidentally helps Pucci understand the requirements of reaching heaven. Pucci's Stand evolves into Made In Heaven and gains the power to accelerate time. In the accelerating time, no one matches Pucci's speed. Trying to save his daughter, Jotaro misses his only chance of defeating Pucci. Then Pucci's attack hits Jotaro during acceleration and splits his face, eventually killed him.
In Other Media
- Jotaro is the main protagonist in the Stardust Crusaders OVAs, voiced by Abie Hadjitarkhani.
- Jotaro is again the main protagonist in the anime adaptation of Stardust Crusaders, voiced by Daisuke Ono
- Daisuke Ono reprises his role in the anime adaptation of Diamond is Unbreakable, voicing the older Jotaro.
- Jotaro appears in the live-action JoJo's Bizarre Adventure movie, portrayed by Japanese actor Yusuke Iseya. Iseya portrays the older version of Jotaro from Part IV: Diamond is Unbreakable, rather than his teenage incarnation from Part III.
Jotaro is a playable character in the following games:
- JoJo's Bizarre Adventure
- JoJo's Bizarre Adventure: Heritage for the Future
- JoJo's Bizarre Adventure: All-Star Battle
- JoJo's Bizarre Adventure: Eyes of Heaven