Like many people with Quirk, Yuga Aoyama manifested his Navel Laser during his early childhood. However, because of a birth defect, Yuga's beams involuntarily leak out from his navel. This led to Yuga developing a certain inferiority complex with respect to other people, to the point of asking his parents why he is so different to everyone.
Later, Yuga received a special belt created especially for him to prevent his powers from leaking out, an item he would wear throughout his childhood.
Yuga is first seen among the students waiting for the U.A.'s Entrance Exam to start. When the exam begins, Yuga comes across a 1-point Villain Bot, defeating it with his Navel Laser. After thanking Izuku Midoriya for his "team-play", he tells him they will not cross paths again and flees the area to collect more points.
Yuga obtains enough points to be admitted to the hero-course at U.A..
Yuga uses his Navel Laser to run the 50m in 5.51 seconds and for the standing long jump. When Izuku Midoriya has his Quirk restrained by Shota Aizawa, Class 1-A homeroom teacher, Yuga gives Ochaco Uraraka comforting words by stating he'll be by her side if Izuku is expelled as she is confused and can't recall his name. However, Yuga is shocked when Izuku uses his Quirk to throw the ball high in the air though states it's not stylish.
Yuga ranked 14th in the test.
When the League of Villain invade the U.S.J., he is warped away by Kurogiri to a unknown place. Yuga is missing the whole time during the Villains' attack, and nobody knows what he is doing nor where he is. It is a mystery that remains secret, but no one seems to care.
On the occasion of the U.A. Sports Festival, Yuga trains for the event. During the first test, as soon as the Obstacle Race start, Yuga avoid Shoto's ice that freezes the vast majority of runners. Yuga manages to finish the race, finishing in position 42, just the last of those admitted to participate in the next trial, and seems to have retained a fair amount of damage for using his Quirk.
He later is among the many asking to be on Katsuki Bakugo's team (though Yuga, instead of asking, assumes that Katsuki would select him), but Yuga is forced to join Hitoshi Shinso's team, along with Mashirao Ojiro and Nirengeki Shoda, when Hitoshi uses his brainwash on him. His team places third, thanks to Hitoshi stealing the points from the Tetsutetsu's team, allowing him to participate in the final event, which is a tournament. When Mashirao decides to resign, Yuga puts his hand on his shoulder and, despite knowing that he was being manipulated by Hitoshi, says that he will not give up. Yuga's opponent in the first round of the tournament is Mina Ashido.
Yuga faces his opponent, Mina, in his first round match. During the match, she causes his belt to malfunction, causing him to panic. She then attacks him with a one-hit KO to his jaw, knocking him out and eliminating him from the tournament.
Yuga along with his class watches the closing ceremony of U.A.'s Sports Festival.
Two days after the Sports Festival, Yuga is in class. During the Hero Informatics Period, Class 1-A has to decide on Hero Names. Yuga writes down and presents his: Shining Hero "I can not stop twinkling." Midnight criticizes the name, thinking it is too long. Midnight suggest he shorten it to Can't Stop Twinkling.
After Class 1-A have finished formulating their Hero names, Yuga is given a list of 40 workplaces in order to choose a workplace that he would like to train at. On the day of the workplace training, Yuga is at the train station with his class so that he can go to the workplace of his choice by train.
On the day of the exercise test, Mr. Principal reveals that Class 1-A will be fighting against U.A.'s teachers in their exercise test. Yuga is paired with Ochaco Uraraka and they must face Thirteen in their test exercise.
Yuga, Ochaco and Thirteen arrive in an uninhabited city where Class 1-A's test exercise will take place. In the city, Thirteen explains the 30-minute test; Ochaco and Yuga 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.
Ochaco and Yuga reach the escape gate but before they can go through it, Thirteen creates a Black Hole, causing the duo to hold onto a guardrail to prevent themselves from being sucked in. Yuga fires his Navel Laser from his knees (thanks to his Hero Costume) at Thirteen but the attempt fails as Thirteen easily sucks away the lasers. Ochaco tries to think of a plan, causing Yuga to surmise that Ochaco is thinking about what Izuku would do; Yuga then asks Ochaco if she likes Izuku, which shocks Ochaco and makes her blush, causing her to let go of the guardrail out of embarrassment. As a result, Ochaco gets drawn towards Thirteen, much to their shared surprise. Facing Thirteen directly, Ochaco instinctively uses her combat skills learned from Gunhead and manages to handcuff Thirteen, allowing her and Yuga to pass the practical test.
Back in class at U.A., Yuga learns that he passed the written test and will go with his classmates to the forest lodge which is a boot camp. Yuga along with his class go to Kiyashi Ward Shopping Mall to buy necessities for the forest lodge.
At some point arrives to I-Island.
Yuga hangs out with the rest of his class after the I-Island Expo opens up.
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.
Following the end of the semester, Yuga is invited by Deku to participate in an endurance training session, along the rest of Class 1-A boys. When Katsuki arrives and challenges Izuku, the boys opt to compete against each other by sprinting down the pool. When is Yuga turn, he tries to reach the other end of the pool using his Navel Laser without touching the water at all. However, in the middle of the flight, he begins to feel a intense pain in his stomach, causing him to deviate and collide with Hanta, who also is trying to reach the other side using his Quirk without getting in the pool. Both students fail into the swimming pool. Shoto wins the race.
After this, all Class 1-A prepare to watch the final race between Izuku, Katsuki and Shoto, but before they can start, Shota arrives and cuts their Quirks off due to their time limit for the pool expiring, kicking all the students out of the pool area.
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. Yuga uses his Quirk to destroy the clay creatures.  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. Yuga trains to get his body used to Navel Laser so that he can keep using it even if his stomach hurts and to increase the range of his laser.
On the night of the third day of training, Yuga is paired up with Momo for a test of courage presented by the Pussycats. Minoru tries to trade partners with Yuga but he refuses. Class 1-A students traverse the forest while Class 1-B students try and scare them in the dark. Their fun event is interrupted by the arrival of the League of Villains' Vanguard Action Squad. The forest is filled with poison gas that leaves most students unconscious.
Momo creates gas masks and rushes through the forest, handing them out to all the students. She joins up with Yosetsu so he can guide her to the students in Class 1-B. Momo ask Yuga to watch over the unconscious Kyoka and Toru and take them back to the facility. Near the Vanguard Action Squad's rendezvous point, Yuga hides behind a bush along with Kyoka and Toru. Yuga contemplates on what to do because he follows Momo’s instructions, but Dabi and Twice’s presence are preventing him from doing that. Dabi seems to spots the bush Yuga is hiding behind, much to Yuga’s fear. Dabi prepares to go and check, however, he stops after Twice informs him that they must also call back Nomu since he only responds to Dabi. Yuga is relieved that Dabi did not discover him.
Izuku, Mezo and Shoto land along with Mr. Compress at the Vanguard Action Squad's rendezvous point; they engage in battles against Himiko and Twice until Kurogiri arrives to retrieve the Vanguard Action Squad. Mr. Compress reveals that he hid the real marbles containing Fumikage and Katsuki in his mouth. Mr. Compress slowly enters Kurogiri's Warp Gate. Suddenly, Yuga fires his Navel Laser at Mr. Compress's face, breaking his mask and causing Mr. Compress to spit out Katsuki and Fumikage.
Thanks to Yuga's actions, Mezo manages to rescue Fumikage, but Dabi grabs Katsuki's marble before Shoto can reach it. Dabi, Mr. Compress and the captured Katsuki teleport away from the training camp.
After the capture of Katsuki, the training camp ends and Yuga returns home. Two days afterwards, Yuga visits Izuku in the hospital. After Eijiro and Shoto state their intentions to save Katsuki themselves, Yuga is also against the idea of attempting to rescue Katsuki along with the majority of the class; Yuga suggests that they leave Katsuki’s rescue to the Pro Heroes since they have been prevented from partaking in combat, to which Fumikage agrees with Yuga.
Following Katsuki’s rescue and the retirement of All Might, Nezu transformed U.A. into a boarding school in order to protect the students. The Height Alliance was built in just three days.
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. Then, Shota scolds the students because he knows that five f them were present at the site of Katsuki Bakugo's rescue and took it upon themselves to rescue him. He also knows that the rest of Class 1-A except Katsuki, Toru, and Kyoka, also knew about their plans but did nothing to persuade them. He further more says he would have expelled everyone but Katsuki, Toru and Kyoka from the school, if it weren't for All Might's sudden retirement.
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. When they check out Yuga’s room, it has an entire set of mirrors of different sizes, as well a large portrait of himself, a disco ball and an armour. They say it is very bright with multiple lights, but Aoyama calls it "dazzling". Mina and Toru completely saw it coming. Later, when they check Kyoka's room, Yuga and Denki comment on how it wasn't ladylike, leading to Kyoka to attack both of them.
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.
Yuga trains his Quirk until the day of the Provisional Hero License Exam. Outside of the National Dagobah Arena, Class 1-A meets with students from Shiketsu High School and Ketsubutsu Academy High School. Before the exam starts, Yokumiru Mera from the Hero Public Safety Commission explains that the first part of the exam involves thinning out the amount of people who can succeed by playing a game, where people put three targets on their body and are given six balls to throw at the other examinee's marks. Those whose targets have been hit are disqualified. Participants need to eliminate two students to move on to the next phase of the exam.
As the exam starts, the students of the other schools focus entirely on U.A. However, Class 1-A is able to defend themselves and avoid being hit by the balls. Yo Shindo tells his fellow classmates that he will shatter their solid defense, and uses his Vibrate Quirk on the ground, unleashing a powerful earthquake that completely shatters the ground and and causing members of class 1-A to disperse. Due to this attack, Yuga gets scattered, and have to defend himself from the attacks of the rest of the participants.
The situation becomes complicated for Yuga, since two of his targets were hit and only had one before being eliminated, so he decides to hide among the rocks. Tenya, who was looking for her classmates, found Yuga and decided to work with him so that they could find their classmates and pass. However, Yuga was content with the rest of Class 1-A passing ahead of him. Tenya refused to leave Yuga behind as he is the president of Class 1-A and as such it is his duty to support everyone including him.
However, they find themselves in the heat of battle against dozens of examinees from different schools ready to take them out. As Yuga thinks that the situation is bad, Tenya saves him from a stray bullet and tells him not to give up. Tenya tells Yuga that as long as he is able he will do his best to serve his class.
Seeing that he is holding Tenya back, Yuga fires his Navel Laser upwards; Tenya wonders what Yuga is planning. Yuga tells Tenya that he has already lost two targets and does not want Tenya to go down with him and thus decided to use himself as a decoy to attract more examinees which will allow Tenya to outspeed and attach his balls to two of them while they are distracted. Yuga admits that his dream is to be equal with everyone else.
Enemy students arrive, but just before they attack Tenya, all the remaining 1-A students make their way towards them, and manage to defeat the other students. On the ground, Yuga is confused as to what is going on; Mina Ashido tells Yuga it is thanks to his Navel Laser that they managed to group up with him and Tenya. The remaining Class 1-A students work together and they begin passing one after the other. Tenya criticizes Yuga that he is the only one that doesn't see himself on the same level as the others, as he's the beacon that allowed Class 1-A to succeed. Yuga and Tenya eliminate their last targets to fill the final two spots for the first phase. With that, Yokumiru announces the end of the first phase.
Yuga waits in the rest room with his classmates 1-A until the start of the second phase of the exam is announced. On this occasion, the students are expected to rescue H.U.C. employees who will act as victims of a large-scale terrorist attack. To help in the rescue operations, Yuga uses his navel laser to create light so other students can see into dark passageways.. At the end of the exam, Yuga is one of the students who passes the exam, receiving his provisional license.
The next day, Class 1-A attend the U.A. opening ceremony. After this, at classes, Shota talks about Hero Work-Studies, hero activities done off campus. Three days later, Shota introduces to Class 1-A the best students of U.A. who will teach them about Hero Work-Studies: Mirio Togata, Tamaki Amajiki and Nejire Hado, better known as The Big 3. Despite they reputation, they are actually all a bunch of easygoing eccentrics. Class 1-A get confused when Mirio Togata challenges them all to a fight.
At Gym Gamma, Mirio tells Class 1-A to attack him whenever and wherever they want. Yuga, like his classmates, attacks him, but his Navel Laser slip right through Mirio's body, without harming him. Mirio counterattacks, and in a few minutes he defeats the entire class 1-A, thanks to his Quirk Permeation. While Class 1-A recovers from their defeat, Mirio explains how his Quirk works and advises class 1-A to participate in the Hero Work-Studies, as it will help them improve their career to be heroes, just as it helped him become one of the best students in the U.A.
Weeks later, after the police raid at the base of Shie Hassaikai, Izuku, Eijiro, Ochaco and Tsuyu return to their dormitories at the school, where Yuga, along the entirety of Class 1-A, is checking to make sure his classmates are doing okay, after their mission.
After a class with Ectoplasm, Izuku and Tenya prepare to go eat lunch, but Yuga approaches Izuku and puts a block of cheese in his mouth and Izuku acts confused and frantic to this situation. Yuga is then refuses Tenya's offer to eat lunch with them. Izuku then states how Yuga's behavior left a strong impact on him, and how Yuga was a man he could never read. Later, Izuku is seen late at night going to sleep as Yuga stares him down as he sleeps through his window.
A while later, Aoyama leaves but used some cheese to say he knows Izuku's secret which he left behind for Izuku as the latter (who was aware of this) gets up and sees the message. The next day, Yuga does his training as he calls out to Izuku and shows him a new move he created: Navel Laser Buffet. He also demonstrates a greater mastery of his Quirk by reducing the size of his laser and writing a French phrase on the stone with it, though it causes him severe stomach problems. Seeing his state, Izuku asks the instructor for permission to take Yuga away from training to recuperate before he asks him what he meant in his message. Yuga explained that he is aware of Izuku not being accustomed to his Quirk and reveals that he went through a similar experience.
Yuga goes on detailing his childhood of having to wear a belt to prevent his powers from leaking out and how he noticed it was similar to Izuku's initial lack of control of his before they both overcame it. He then tells Izuku he is not alone in hardships as its better to face them together or they won't excel. His words cause Izuku to smile and thank him for his support before Yuga suffers from another stomach problem. After a few days, he and Izuku become good friends with some of the class noting Yuga's more livelier attitude and his association with Izuku.
Days later, in the classroom, Shota Aizawa announces that U.A. High School will be having a School Festival and tells Class 1-A to pick out a program to perform at the festival. The 1-A students are all brainstorming ideas for the upcoming culture festival, but they do not reach an agreement. Later at Heights Alliance, the entire Class 1-A decides that their school festival program will be a live performance and dance with party space.
The next day, they choose the members that will be part of the music band. Looking for a singer for the band, a few students try out for the position. As it turns out, Eijiro can't get the right genre, Yuga is a falsetto, and Minoru can't sing at all. At the end, they decide that Kyoka will be the singer.
Later, the students decide who will be part of the dance team and the staging team. Yuga ends up being part of both since Mina's plan for Yuga is use him as some kind of human disco ball. He will dance but he will also be responsible for providing lighting effects with which to ambience the music performance and encourage the public. Class 1-A begins to practice for the festival. After a few days of training, Mina tells Izuku that he is being switched over to the Staging Team from the Dancing Team, to help maneuver Yuga during his part of the presentation, although he will still be able to perform. He is selected since he and Yuga have been getting along as of late. Class 1-A continues to practice until the day of the festival.
The night before the event, Yuga and Izuku find that the rope they will be using to suspend Yuga in mid-air for his part in the routine is now frayed. Not wishing to disturb Momo who had gone to sleep, Izuku says he will go buy a new rope from a store early next morning. During the purchase, Izuku meets two villains who face and defeat, but they delay him for the performance.
Yuga Aoyama is waiting for Izuku to return. Izuku arrives with the new rope. Yuga inquires about Izuku's injuries, to which the latter excuses as having fell. Izuku he cleans up his face before going on stage. no more incidents occur and the music performance of class 1-A ends up being a huge success.
As November comes to a close, the Wild Wild Pussycats pay a visit to Class 1-A to celebrate Ragdoll's reinstatement.
Not long after, after a training and after training and going to bed to sleep, Yuga wakes up after hearing a loud noise coming from Deku's room. He walks over to Izuku's room, which has the door left open, and finds the room a mess, the bed covers ripped to shreds and Deku clutching his glowing hand, which is coursing with the power of One For All.
Despite this, Yuga think that the reason of Izuku's thrashing was that he didn't stockpile enough cheese and wanted more. To keep him from discovering the true, Izuku decides to lets Yuga think he got it right.
Shota Aizawa and Vlad King hold a Joint Training Battle between their classes during the early days of winter. Yuga is placed in a team with Fumikage Tokoyami, and Toru Hagakure and lead by Momo Yaoyorozu, to compete against Class 1-B formed by Kinoko Komori, Shihai Kuroiro, Manga Fukidashi and lead Itsuka Kendo, in the second round of match-ups.
Upon the beginning of the second match, Fumikage uses Dark Shadow to scout out their opponents with Yuga commenting on the increase in range that he can send out Dark Shadow after his Hero Work. However, Dark Shadow gets hijacked thanks to Shihai's Quirk and attacks Fumikage. Shihai exits Dark Shadow and evades two nets created by Momo by merging with the shadows between the pipes.
Shihai mocks Tokoyami and moves through the shadows. Class 1-A believes Shihai will target Fumikage, however he sneaks up behind Yuga and grabs him and pulls him away. Fortunately for Yuga, Fumikage had developed a new super move called Black Fallen Angel that allows him to fly, so he soars past Shihai and rescues Yuga from him. Momo tells Yuga to use his Navel Laser Buffet to blast the area with laser beams. The light of the breams disrupts and warps the shape of the shadows and takes away all Shihai's hiding spots. With Shihai unable to hide in any shadows, Momo instructs Toru to grab him but Kinoko uses her Quirk to cover everything in Mushrooms. 
Everything goes according to Itsuka's plans. She predicted Class 1-A team would use Yuga's Navel Laser to attack Shirai, without foreseeing that the light would also reveal their location, giving Manga and Kinoko the opening to barrage Class 1-A with their long ranged Quirks. Manga quickly spawns giant text with his quirk, cutting Momo off from the rest of her team. Yuga tries to blast the text with his laser, but he cannot damage it 
Shihai moves through the shadows of the mushrooms and captures Yuga again. Fumikage tries to save him but Manga knocks him down with text bullets. Thanks to this, Shihai successfully locks Yuga in jail, eliminating him from the round. Yuga's teammates are still fighting and almost manage to win but, in the end, Class 1-B team are the ones who achieve victory in the second round.