At a young age, thanks to the influence of her parents, Kyoka developed an interest in music, eventually learning to play several instruments.
Despite her parents desires for her to become a musician, she decided to become a hero instead because she wanted to dedicate her work to others. When she told her parents about her plans, they were happy for her and let her walk her own path.
She is teamed with Denki Kaminari as "Team G" after being randomly drawn, participating as the Hero team. Kyoka uses her Earphone Jack to locate the rival team, indicating it to Denki, who advances with his Quirk ready to be used. It is unknown how well they both did in the trial itself.
When actual villains invade, Kyoka is warped to the mountain area of the Unforeseen Simulation Joint along with Momo Yaoyorozu and Denki Kaminari. Annoyed that Denki is complaining too much, she kicks him into one of the villains, causing the villain to be electrocuted by Denki's Electrification. She then uses her Quirk to protect Denki from an attack by one of the villains.
Kyoka plugs her jacks into her boots to launch a sonic attack, causing the villains to block their ears in pain, which gives Momo the time needed to create an insulator sheet. Kyoka and Momo hide under the insulator sheet while Denki discharges a great amount of electricity, defeating the villains while Kyoka and Momo remain unharmed.
However, one of the villains takes the air-headed Denki hostage, forcing Kyoka and Momo to stop fighting back and remain motionless. Kyoka attempts a sneak attack by distracting the villain through conversation, but fails.
Fortunately, the villain holding Denki is shot down by Snipe, freeing Denki, with Kyoka rushing to tie up the villain. She is then seen with her class after the battle with the League of Villains is over.
After Shota announces that the Sports Festival is approaching, Denki says that he plans to become a Pro's sidekick after he graduates, to which Kyoka states that many people become sidekicks and fail to become real Heroes, to which she thinks that Denki is the kind of person who would become like that, which causes Denki to become crestfallen. Kyoka competes in the Obstacle Race where she places 21st, allowing her to compete in the Human Cavalry Battle.
In the Human Cavalry Battle, she teams up with Rikido Sato, Koji Koda, and Toru Hagakure while Toru is the rider. When the Human Cavalry Battle begins, Kyoka uses her Quirk to try and grab Izuku's headband like Tetsutetsu Tetsutetsu told her, but Fumikage uses his Dark Shadow to block her attack. Later in the Human Cavalry Battle, her team charges towards Shoto Todoroki's team, but her team gets zapped by Denki and frozen by Shoto's team. Her team fails to qualify to the next round when her team lost the Human Cavalry Battle.
After Denki and Minoru state that the girls must do the cheering battle as per orders from their homeroom teacher, Kyoka and the other girls of Class 1-A walk out in cheerleading outfits. However, as Kyoka and the girls walk out, they realize they have been tricked. Kyoka then calls Denki and Minoru idiots. During the recreational events, Kyoka is seen sitting still in her cheerleader outfit while watching Mina, Ochaco, Tsuyu, and Toru cheerlead.
As the match between Ochaco and Katsuki begins, Kyoka comments that she might look away the entire time. During the match between Ochaco and Katsuki, Kyoka averts her eyes from the match when seeing Katsuki's explosion assault on Ochaco.
Kyoka along with her class watches the closing ceremony of U.A.'s Sports Festival.
Two days after the Sports Festival, Kyoka is in class. During the Hero Informatics period, Class 1-A has to decide on Hero names. Kyoka gives Denki an idea for his Hero name: Jamming Way, causing Denki to reply that her idea was good, as it references the intellectual: Hemingway. But Kyoka revealed she was just using that name as a means to make fun of Denki, leaving him disappointed. Kyoka writes down and shows her Hero name to her classmates. Kyoka reveals her Hero name to be Earphone Jack, the Hearing Hero.
After Class 1-A has finished formulating their Hero names, Kyoka is given a list of 40 workplaces in order to choose a workplace that she would like to train at. On the day of the workplace training, Kyoka is at the train station with her class so that she can go to the workplace of her choice by train.
Kyoka choses Death Arms for her Hero Agency Internships. Death Arms works out Kyoka hard in the field. He makes her run during patrol and she barely keeps up with him. Kyoka thinks to herself about much harder her training is compared to school. Later, Kyoka helps Death Arms rescue civilians from a hostage situation. She uses her Quirk to figure out how many hostages were taken. Kyoka escorts them both to safety after Death Arms rushes in.
The workplace training comes to an end and Kyoka returns to U.A. After Foundational Hero Studies is finished, Kyoka catches up with Tsuyu and Mina and she is amazed by Tsuyu's activities. She is among the students bearing witness to the gamma race, where she and Momo count Izuku out since his Quirk has repercussions. They are quickly proven wrong when Izuku shows off his new moves and they are surprised as well as amazed at his better control of his Quirk and lead in the race until he trips causing him to lose.
Later on, Kyoka is in the girls' locker room where she uses her earphone jacks to hear Minoru's plan to peek on the girls. Kyoka plugs one of her earphone jacks into the hole which stabs Minoru's eye, stopping Minoru from peeking. Though thanked by the other girls, an embarrassed Kyoka wonders why she was the only one he did not mention.
One week before the end of term test, Kyoka asks Momo to help her study. Throughout the final week before the end of term test, Kyoka studies under Momo's tutoring along with Denki, Mina, Mashirao and Hanta. On the day of the exercise test, Mr. Principal reveals that Class 1-A will be fighting against U.A.'s teachers for their exercise test. Kyoka is paired with Koji and they must face Present Mic in their exercise test.
Koji, Kyoka and Present Mic arrive in an uninhabited city where Class 1-A's test exercise will take place. In the city, Kyoka mocks Present Mic for what she takes as a poor reference, to which Present Mic tells her to be careful with what she says. Present Mic explains the 30-minute test; Kyoka and Koji must either handcuff him or one of them must escape the battlefield within 30 minutes in order to win and pass the test. The test begins.
Kyoka plugs in her Earphone Jacks to try and block out Present Mic's loud voice, but to no avail. Annoyed by Present Mic's loud voice, Kyoka tells Koji to command the nearby animals to attack but Koji is unable to due to Present Mic's voice making the animals wild and as a result, any command he gave would be useless.
Kyoka and Koji manage to get a little closer to the escape gate, but Kyoka notes that Present Mic will be at the escape gate and that no matter what option of victory they choose, a standoff is inevitable. Present Mic uses his loud voice again; Kyoka notes that they cannot get any closer as long as Present Mic is using his Quirk. Kyoka sees an ant and comes up with an idea; she asks Koji if he can control bugs but his terrified reaction indicates that he doesn't like bugs. Present Mic uses his loud voice once again; Kyoka tries to counteract with her Earphone Jacks and use Heartbeat Fuzz to counter Present Mic's voice.
Present Mic continues using his loud voice against Kyoka and Koji who are unable to handle it. Out of options, Kyoka asks Koji if he can control insects to which he approves. Kyoka uses her Earphone Jacks to break a rock which reveals dozens of insects, much to Koji's terror. Kyoka tells Koji that she understands his phobia but using the insects to attack Present Mic is the only plan she can think of because their opponent is too strong. Kyoka encourages Koji to follow through with her plan.
After seeing Kyoka's bleeding ears, Koji is ashamed that he is running away from this fight and realizes that he can only continue being at U.A. by overcoming his fear. Koji musters up the courage and commands the insects to attack Present Mic while Kyoka is annoyed he picked that moment to talk. At the escape gate, Present Mic sees that time is nearly up. Suddenly, dozens of insects crawl on Present Mic, who realizes that the insects traveled to him by moving underground; a place where sound is ineffective. Present Mic is paralyzed by fear, allowing Koji to run through the escape gate while carrying an injured Kyoka with him; thus they pass the practical test.
Back at U.A. in class, Kyoka learns that she has passed the written test and will go along with her classmates to the forest lodge which is a boot camp. Kyoka accompanies her class to the Kiyashi Ward Shopping Mall to buy necessities for the forest lodge. At the shopping mall, Kyoka says that she requires a big carrying bag, to which Momo tells Kyoka that she will help her look for it.
Due to a shopping center incident, where Izuku had an encounter with Tomura, Shota informs Class 1-A that the destination for their lodge trip has been changed and the new destination will only be announced on the day of the event. The first semester has come to a close and summer break has begun.
On the day of the summer camp, they are informed that the new destination will be a mountainous region, owned by the professional Hero Team, the Wild, Wild Pussycats, where they will undergo reinforcement training to strengthen and upgrade their Quirks which will also allow Class 1-A to obtain their temporary licenses. Class 1-A’s bus stops for a restroom break, where they meet Pixie-Bob and Mandalay, who challenge the students to reach base camp past the forest in three hours. Then, all Class 1-A is forcibly thrown into Beast's Forest by Pixie-Bob's Quirk.
To reach their destination, they must traverse the forest, which is inhabited by dozens of hostile earth monsters created by Pixie-Bob. The Students work together to fight their way through the forest. To help her classmates, Kyoka, along with Mezo, use her Quirk to detect the location of the approaching beasts. The journey through the forest to the Cabin takes them around eight hours before finally arrive at the facility, battered and tired. Class 1-A fetch their luggage from the bus and put it in their rooms, and later go to the dining hall and the Pussycats serve dinner.
The next morning, Class 1-A are outside the training camp cabin. Shota greets his students and tells them that they will undergo reinforcement training to strengthen and upgrade their Quirks. She trains to increase the quality of sound from her Quirk by strengthening her Earphone Jack by constantly hitting a rock with the jacks of her earlobes. Afterward, Class 1-A and 1-B are tasked with cooking for themselves. During dinner, Kyoka punches Hanta for making an unfortunate comment about Momo’s Quirk, saying that her ability to create things from her body after eating is like pooping.
During the third day of the lodge trip, while Classes 1-A and 1-B are undergoing their Quirk-strengthening training, Pixie-Bob announces both classes that tonight they will be playing a game, a test of courage. Kyoka does not like this idea because she hates scary things. Later, that night, Kyoka is paired with Toru, being the third pair to enter the forest where the test takes place.
At that moment, the Vanguard Action Squad attacks the training camp, filling the forest with poisonous gas. Kyoka and Toru are unconscious because of the gas, being later found by Momo and Yuga. Momo had created several gas masks, and placed two on the faces of her classmates to protect them. After this, Momo asks Yuga to take the unconscious Kyoka and Toru back to the facility while she leaves to help, while she looks for the students of class 1-B.
Kyoka and Toru are hospitalized because of the gas, not knowing that the Vanguard Action Squad members manages to kidnap Katsuki.
After Katsuki is captured by the Vanguard Action Squad, Kyoka is taken to hospital in the hopes that she regains consciousness. Eventually, Kyoka regains consciousness, recovers and returns home. Shota and All Might visit her house and speak to her parents regarding relocating the U.A. students to the dormitories. Kyoka's father is initially hesitant, but Kyoka tells Shota not to worry since her father has already agreed to send her to the dorms since he is actually happy that her daughter will become a powerful hero like All Might after witnessing his fight on TV.
Due to the attack of the villains, and after Katsuki's rescue and All Might retirement, As a security measure, Nezu decides to build the Heights Alliance, a group of buildings inside the campus, where the students reside. The Height Alliance was built in just three days. It is meant to protect the students and allows the teachers to keep close surveillance on the students.
Shota Aizawa meets with his students outside of the building. He states they must start preparing to get Provisional Hero Licenses like they had planned to during the training camp. Before they can enter, Aizawa reads the riot act against Izuku, Tenya, Momo, Eijiro, and Shoto for participating in the Katsuki’s rescue, breaking the rules in the process, and the others who did nothing to stop them from doing it through the proper channels, stating that aside from Katsuki, Toru and Kyoka (the first for being kidnapped and the other two for being unconscious in the hospital when everything happened) he would have expelled all of them for their actions, if it weren't for All Might's sudden retirement. After this, he allows students to enter their new home.Class 1-A arrange their luggage in their respective bedrooms. Later that night, the boys of Class 1-A are in the common space on the first floor. The girls of Class 1-A show up and Mina Ashido suggests a room showcasing competition. After checking the boys 'room, it's time to check the girls' room. Kyoka's room is the first of the girls that they visit, to her displeasure
Her classmates are surprised when seeing the musical theme of her room full of musical instruments, records, and decorative elements that make reference to rock, leading to Denki and Yuga commenting on how it wasn't ladylike, leading to Kyoka to attack both of them. Back in the common space on the first floor, she votes Rikido Sato the winner, solely because of his cake.
The following day, Shota tells to Class 1-A that their next goal is to obtain their "Provisional Hero Licenses" Shota announces that they will be working on developing their own special moves, much to the class' excitement. The class visits the Gym Gamma, where Cementoss creates a training ground for the class with Ectoplasm using his Quirk to create villains for the class to practice their moves on. Kyoka updates her hero costume and adds a set of headphones and two bracelets that double up as her amplifiers. 
The day of the License Exam, Class 1-A goes to the place where the tests will take place and here they meet other students from different schools, like Shiketsu High School and Ketsubutsu Academy High School. Later, the organizer of the exam explains to all the participants the rules of the first test, giving all the targets and informs the students that they will have to insert particular balls in the opponents' targets in order to qualify. Those whose targets have been hit by the balls are disqualified. Participants need to eliminate two students to move on to the next phase of the exam.
When the first trial begins, all the opposing students are thrown against the students of the U.A., who find themselves having to defend themselves against a large number of attacks; Kyoka deflects balls coming from the subsoil with her new special move Heartbeat Fuzz. However, a boy from an opposing school uses his Quirk to divides the U.A. students.
After the attack, Kyoka regroups with Tsuyu, Mezo and Momo. In the city area the go to a building with an observatory deck to located more classmates. They do not know that they have fallen into a trap of Saiko Intelli of Seiai Academy.
With no luck, Kyoka uses her Earphone Jacks on the wall and informs them that she hears four people coming. She soon realizes that they aren't stopping on any floor but coming directly towards them. Suddenly, Kyoka gets hit by a high-volumed speaker playing music against the wall. The group soon realize it's a coordinated attack. The windows are shattered, Tsuyu and Momo suspect the opponents are waiting for the right time to strike. Kyoka impulsively prepares her super move but is countered and her left ear and arm amp get damaged by an aim Quirk.
Seiai Academy continues their plan by freezing the air conditioner. Kyoka suggest creating an electric heater but Momo says that won't work because the enemy mostly have control of the electricity. Kyoka also suggest creating bomb but Momo says that won't work either due to the unpredictable damage it will cause. Momo comes up with a plan and creates four headphones and a large amp. Everyone puts on the headphones and Kyoka connects her undamaged Earphone Jack and creates a sonic attack. The sound force rattles Kyoka's body but she holds it in.
After a successful counter attack all of the Seiai Academy group is immobilized except Saiko Intelli. Saiko grabs Momo and takes her back to the room Momo had just escaped. Kyoka and the other two come to her aid and save Momo. Saiko questions why they didn't just leave Momo to fail but Kyoka states class 1-A sticks together.
They make it back to the refreshment area, where they met up with Shoto and discover that they're the only ones who have passed so far from their class. Minutes later Katsuki, Denki & Eijiro arrive, where Kyoka comments that Denki probably slow downed Katsuki. After awhile the rest of class 1-A pass the first qualifier test.
The qualifiers are informed of the imminent start of the second test, in which the students will have to save the largest number of fake victims in a given period of time. Kyoka uses her Quirk to locate victims during the second test.
At the end of the trial, Kyoka and her friends are shown the results and the girl is happy to see her name on the list of those who received a Hero License.
Next day to the Provisional Hero License Exam, Shota tells Class 1-A about Hero Work-Studies, hero activities done off campus, saying that it is a more formalized version of the Field Training they did with pro heroes before. Three days later, Shota Aizawa introduces Class 1-A to the people who will teach them about Hero Internships; the third-year students who rank among the top of all U.A. students known as The Big 3: Mirio Togata, Tamaki Amajiki and Nejire Hado.
The personalities of the three students leave Class 1-A confused, who get even more confused when Mirio challenges them all to a fight. At Gym Gamma, Mirio tells Class 1-A to attack him whenever and wherever they want. Kyoka, along her classmates, tries to fight him but thanks to his Quirk Permeation, Mirio easily defeats all students of Class 1-A.
As Class 1-A recovers, Mirio states that the reason he wanted to fight Class 1-A is to show the experience he gained from the Hero Work-Studies. Thanks to that, Mirio was able to make his Quirk more powerful and reach the top. Class 1-A applauds Mirio's speech and they realize what the work-study could do for their skills.
Weeks later, Kyoka see the news about the police raid at the base of Shie Hassaikai, raid in which Izuku, Eijiro, Ochaco and Tsuyu participated and in which there were some casualties. When they return to their dormitories at the school, the entirety of Class 1-A checking to make sure their intern classmates are doing okay, physically and mentally, after their mission.
At Heights Alliance, after seeing Mina's dancing skills moves, Denki comments that Kyoka's hobby towards music is also impressive, and talks about her music themed room, which Kyoka shyly asks Denki to stop commenting on it. Later in the classroom, Shota Aizawa announces that U.A. High School will be having a School Festival.
Shota explains that the festival is sponsored by the other U.A. departments. However, Shota points out that part of the festival will be within U.A. and tells Class 1-A to pick out a program to perform at the festival. Tenya Iida asks ideas from Class 1-A; but the class ends without reach an agreement.
Back at Heights Alliance, Tenya believes that Class 1-A should do a program where everyone can blow off steam. Mina suggests dancing, to which Shoto Todoroki unexpectedly agrees. Then Minoru reminds them all that dancing requires music, so the whole class looks at Kyoka.
Though, Kyoka believes that music has nothing to do with heroism and is simply just a hobby, Denki says to her that he finds it really awesome that she can play so many instruments. Then, Koji tells her that playing music can help put smiles on people's faces. Encouraged by her peers, Kyoka decides to help Class 1-A with music. All of them agreeing with dance and music, Class 1-A's school festival program will be a live performance and dance with party space.
Next day, they decide who will be the members of the musical band. Kyoka Jiro suggests club rock and asks if anyone can play instruments such as drums. Denki Kaminari remembers Katsuki having experience in playing drums which Hanta Sero agrees to. Katsuki's performance with the drums impresses Kyoka who wants him for the band. Although at the beginning Katsuki seems disinterested with performance, he announces that he will blow everyone away in U.A. with his sound. Kyoka and some of Class 1-A are surprised with Katsuki's willingness to participate; Kyoka also decides to do her best.
Momo Yaoyorozu suggests playing the piano, having grown fond of playing it since her etiquette training in her childhood. Kyoka Jiro approves of Momo's choice. Ochaco Uraraka asks Kyoka if she has someone for vocals in mind. Eijiro Kirishima, Minoru Mineta, and Yuga Aoyama try singing but are not good enough. Eijiro suggests that Kyoka sings. After hearing Kyoka's beautiful voice, everyone unanimously agrees that she will be Class 1-A's vocalist and also will play the bass.
Kyoka asks two volunteers for the guitarist positions, Denki Kaminari and Minoru try out; the former being able to perform well while the latter is unable to reach the guitar strings. Fumikage Tokoyami picks up the guitar left by Minoru and starts playing a heart rending sound, impressing his fellow classmates.
An hour past midnight, an exhausted Tenya Iida states that they have all of Class 1-A's roles for the dance hall live performance organized: Kyoka, Momo, Katsuki Bakugo, Denki, and Fumikage form the band; Eijiro, Hanta Sero, Koji Koda and Shoto Todoroki form the staging team; and everyone else will be part of the dance team.
Until the festival, the Band team constantly practices under the lead of Kyoka. To help her bandmates, Kyoka writes notebooks with tips and advices for each member of the band. When Izuku notes that everyone will be so happy to see this, Kyoka admits she wrote it precisely to hear someone say that.
The night before the festival, Kyoka tries to calm the excitement of some of her classmates, saying that feeling shy or nervous won’t do them any good. Once they are on stage, they just have to enjoy themselves.
On the appointed day, Class 1-A carry out their music and dance performance. They manage to put up a flashy introduction and manage to pump the audience with their signing and dancing. As the rest of the audience cheer on, Kyoka thinks back to telling her parents her plans on becoming a Hero. Kyoka's mother and father support her decision saying that she can do whatever she wants. Class 1-A's performance ends up being a huge hit.
Shota Aizawa and Vlad King hold a Joint Training Battle between their classes during the early days of winter. Each class chooses lots to split into five teams of four. As the teams are set, Kyoka is placed with Rikido Sato, Hanta Sero and Katsuki Bakugo, who leads the team. They will face Class B's team of Yosetsu Awase, Kojiro Bondo and Togaru Kamakiri and leading by Setsuna Tokage at Round 4.
Katsuki wants to take the lead and charge ahead with the others serving as back up. He tells Kyoka to pick up on the sounds coming from the Class 1-B team and to figure out their location. Class 1-A charges through Ground Gamma towards the enemy. Katsuki yells at his teammates saying that they are too slow. Kyoka says that she is trying to listen to the sounds as she goes to which Katsuki says to forget about it and to just hurry up and follow him.
Katsuki notices someone up ahead and tells Kyoka to use her Quirk hurry and find their location. She proceeds to do so and notices there are dozens of sounds that lead them into a trap. She tries to warn her team but it's too late. Setsuna's detached mouth sneaks up behind Katsuki and confirms the ambush. Setsuna's Lizard Tail Splitter lets her spread out her separated limbs throughout the field and uses her tiny body parts to attack. Katsuki gets bombarded by Setsuna's Quirk.
Hanta uses Barricade Tape to protect his team, so that the lizard parts cannot attack and proceeds to call Katsuki over. Setsuna tells Kojiro it's his turn and he uses Glue Squall spread his adhesive all over Hanta's tape barricade. Togaru watches the Class 1-A team struggle and uses his Quirk to slash a large pipe that crashes down toward the other team. Rikido prepares to sacrifice himself and catch the falling pipe but Katsuki manages to fire a large enough explosion that destroys the glue covered pipes and barricade.
With the barricade gone, Togaru believes Katsuki's actions destroyed his team's protective shelter and dives towards the Class 1-A team to attack them. Setsuna orders him to take out Kyoka first because her Quirk is the most troublesome. Just as Togaru is about to land a fatal blow, Katsuki appears and kicks Kyoka away, hitting Togaru him with a powerful explosion at point-blank range.
Class 1-B members are surprised with the behavior of Katsuki, causing they plan to fail, leaving them totally unprepared. Kyoka tries to hone in on Class 1-B but Setsuna's interference makes it difficult. She does notice that there are fewer sounds than before and Class 1-B is retreating. Katsuki surmises they're trying to regroup. He is not willing to allow it and chase them.
Yosetsu traps Katsuki with his Construction-Done-Kwik: Weldcraft, but Rikido acts quickly and free Katsuki from his restraints. Katsuki flies at Yosetsu, who then tries to protect himself by attaching multiple steel plates to his body. It turns out that Katsuki was merely tricking him by blasting upwards and lets his teammates take out the enemy. Hanta carries Kyoka to the fight and she attacks Yosetsu with Heartbeat Surround, stunning him. Then, Hanta wraps up Yosetsu. Then Kyoka directs Katsuki towards the remaining members of 1-B. One by one the members of the class 1-B team are defeated and captured by Class 1-A, with little to do to counterattack or defend themselves.
The fourth Round of the Joint Training Battle ends with Class 1-A scoring a perfect victory with 4-0. Shota Aizawa commends Team 1-A for being able to cooperate well enough to reduce battlefield damage and efficiently capture the opposing opponents without any hassle. Class 1-A congratulates the winning team, with Denki remarking on Katsuki's abilities and calling Kyoka a true "heroine".
Kyoka interns under Gang Orca alongside Mezo Shoji.