Since he was a child, Neito has always wanted to be a hero. However, due to the nature of his Quirk, people constantly told him that this was not possible, because he can not do anything without the help of others, being ridiculed by that. Although this did not make him desist in his efforts to be a hero, he did understand that to fulfill his goal, he has to resort to unheroic behaviors and tactics.
At the opening ceremony for the U.A. Sports Festival, Neito takes the field with his fellow classmates in Class 1-B. He is able to qualify for the Cavalry Battle after taking thirty-sixth place in the Obstacle Race, purposefully placing low.
While forming teams for the Cavalry Battle, Neito gives a small speech to his peers. He says that all the fans are too focused on Class 1-A just because they fought a few villains, and he believes Class 1-B isn't second rate and, telling his classmates to step their game up and show Class 1-A what they can do. Neito forms his team with Kosei Tsuburaba, Sen Kaibara, and Shihai Kuroiro.
Before the Cavalry Battle begins, Neito tells Tetsutetsu Tetsutetsu that there are no hard feelings between their teams. Soon after the round begins, Neito is able to steal Toru Hagakure's headband with ease. He follows up by stealing the headband of Katsuki Bakugo. After stealing Katsuki's headband, Neito takes a moment to explain his strategy from the Obstacle Race, explaining that he and some of his classmates threw the Obstacle Race in order to scout Class 1-A's Quirks; remaining at the back down the lower end of the top forty to keep a low profile, while from the front, Katsuki and his class freely exposed their Quirks to everyone watching. Neito comments that it was foolish on their part to obsess about the preliminary round and continues to taunt Katsuki, talking about how he's is famous for being the victim of the Sludge Villain incident. Now furious, Katsuki promises to eliminate Neito's team.
Sen pleads for him to stop provoking Katsuki, which Neito apologizes for, saying, probably sarcastically, it was unheroic of him, but even so, Neito says Katsuki is like a moronic villain desperate for revenge. Greatly irritated, Katsuki attacks, but Neito evades and counters using Katsuki's own Explosion on him. Then, Neito quickly touches Eijiro Kirishima and uses his Quirk to block the subsequent strike. Katsuki then realizes Neito's Quirk is the ability to copy other peoples powers, and Neito says he's impressed that even an idiot like him could figure it out. When Katsuki tries to attack again, Neito's classmate: Kojiro Bondo uses his Quirk to immobilize Team Bakugo.
As other teams close in, Team Monoma turns to leave the area, deciding to stay away from the other teams for the remainder of the match and just let the clock run out, but not before Neito fires one last shot at Katsuki, sarcastically wondering if he could really keep to the pledge about winning he made at the beginning of the sports festival. In a fit of rage, Katsuki flies at them, jumping away from the rest of his team, and Neito, a little panicked by this sudden attack, orders Kosei to block him with his Solid Air Quirk. However this does little to deter Katsuki, as he simply punches through the wall of air and grabs two of Neito's headbands, before being pulled back to his team by Hanta Sero's Tape. Other teams try to capitalize on Team Monoma, but Kosei manages to repel them with his Quirk, and he realises that, with one high-scoring headband left, they're still in fourth place, Neito agreeing to settle for this as it's still a qualifying place.
But Katsuki clearly isn't finished with Neito, as him and his team quickly close the distance between the two teams, readying himself for another attack. Kosei tries to stop him, but, again, Katsuki just blasts through the air shield, takeing Neito's last headband. The Cavalry Battle ends, and without any points, Team Monoma fails to advance to the finals.
Having been eliminated from the primary competition, Neito reluctantly participates in the recreational activities provided prior to the final round. He takes notice of all the Class 1-A students doing their best in the activities and insults them for taking the recreational games too seriously.
During the scavenger hunt, Itsuka Kendo turns Neito in since she needs a "perverse person". Neito says that she may have the wrong impression of him, but she claimed it was fine,  and when Ibara Shiozaki easily defeats Denki Kaminari, Neito taunts Class 1-A, then Itsuka restrains him with a blow to the back of his neck, and apologizes to them for his behavior. Five fights later, Neito is seen paying close attention to the duel between Katsuki and Ochaco Uraraka, noticing Ochaco's strategy long before many of the other viewers, commenting that some of them need to look closer at the battle, and when Ochaco finally makes her move, he explains her plan of action to his class. After Katsuki defeats Fumikage Tokoyami in the semi-finals, Itsuka teases Neito by saying that he chose a scary person to make an enemy out of, but he just replies that Katsuki was just lucky his Quirk worked so well in that matchup. In the Sports Festival's closing ceremony Neito joins his class in honoring the first, second and third place winners.
Just prior to the end of their first term, Neito confronts Class 1-A in the lunchroom, purposely bumping his arm against Izuku Midoriya's head, taunting him about his encounter with the Hero Killer: Stain, and asking him, somewhat sarcastically, what sort of villains they would bring down upon the rest of the school. Itsuka steps in and knocks Neito out with a single chop, apologizing for his behaviour and telling them about what Class 1-B were told will be in the final practical, which was the topic of their conversation before Neito's interruption. He regains consciousness towards the end of their conversation, and berates her for sharing information, but she just knocks him out again and drags his unconscious body away.
Following the end of the first semester at U.A. High, Class 1-B joins Class 1-A for training camp over summer break. While boarding the buses to head to the forest lodge, Neito taunts Class 1-A about some of their students failing the final exams. Itsuka knocks him out to stop him and drags him onto the bus.
When Class 1-B arrives at the training camp, their homeroom teacher Vlad King explains that they will be extending their Quirks and that the more they use their Quirks, the stronger they will be by breaking their limits. The next day, Neito participates in taking extra lessons with the five members of Class 1-A who failed in the finals. Despite having failed himself, he taunts them since more people failed in 1-A than 1-B.
Mandalay sends out a Telepathic Message that the training camp is under attack, and Neito questions how that's possible since the camp was supposed to be a secret. Shortly afterward, Dabi attacks the extra lessons group's classroom, but Vlad King and Shota Aizawa stop him, Neito praising his homeroom teacher's skill.  However, when the villains succeed in their mission of capturing Katsuki, Neito and other students feel devastated at the loss of one of their classmates.
To prepare for the upcoming Provisional Hero License Exam, Vlad King has Class 1-B train at Gym Gamma, and when they arrive for training, Vlad King tells Shota to excuse his class. In his hero costume, Neito taunts Class 1-A once again about competing with them in the exam, and when the teachers explain that the two classes won't compete against one another and Neito actually appears to be relieved, although he covers this up as best he can with more mocking comments. 
When U.A. schedules for an assembly outside the school's dormitories, Neito greets Class 1-A with mockery. He reveals that he heard that two of their classmates failed the Provisional License Exam, laughing at their apparent "failure". Eijiro then questions whether Neito again failed the exam, only for the latter to reveal that all of Class 1-B have passed the exam, including him. Neito proceeds to trick his classmate Pony Tsunotori into trash talking Class 1-A when she informs them of an upcoming joint training session. Neito gives Pony a thumbs up after she unintentionally insults the Class 1-A, in which Itsuka scolds him for teaching the young girl bad phrases while knocking out him out as usual. 
Neito, along with the rest of Class 1-B, is preparing a fantasy play dubbed "Romeo, Juliet and the Prisoner of Azkaban: The Return of the Kings", where he plays the role of the main character Romeo. Likewise, Neito registers Itsuka in the Beauty Contest, forcing her to participate. He does it because Itsuka is popular and therefore has a chance to win which would increase Class 1-B’s prestige, and also because, while Itsuka is busy with the contest, he is free from her hand chops.
He comes across Izuku and Mirio Togata, while they take Eri on a tour around U.A. As usual, Neito flaunts Class 1-B’s superiority and boasts about the show his class is rehearsing, until Yosetsu Awase whacks him with a board and apologizes for his actions, explaining to them that Itsuka isn’t around to restrain him because of the Beauty Contest. Mirio apologizes to Eri for U.A.'s "dark side": Neito.
Neito loudly announces the arrival of Class 1-B, claiming that the momentum is now moving to their side. Neito presents the results of a questionnaire he published, showing that there was a two-vote preference for Class 1-B's performance in the School Festival over Class 1-A's. As Neito continues to shout and taunt Class 1-A as they begin their first joint training, Itsuka and Yosetsu both move to scold him but Shota intervenes first by strangling him with his binding cloth. They then learn they will have a special guest: Hitoshi Shinso, who is trying to transfer to the hero course.
Neito becomes excited once Hitoshi mentions that he's not participating for the sake of making friends. Upon selecting teams, Neito is paired with Yui Kodai, Nirengeki Shoda, Reiko Yanagi, and Hitoshi for Round 5. Neito immediately welcomes Hitoshi with open arms, happily willing to cooperate with the hero-in-training in hopes of crushing Class 1-A. Throughout the matches, Neito comments on his class' performance while insulting Class 1-A with increasing signs of insanity, much to the dismay of his team.
During Joint Training Battle/Round Four, Neito expects that Katsuki will behave recklessly and allow his team to fail. However, he is flabbergasted to watch Katsuki save Kyoka and cooperate with his comrades in battle. Neito learns from Denki and Eijiro that this isn't new since Katsuki has developed and he is unable to comprehend Katsuki's teamwork and victory over his class.
Upon taking a first glance at the hero-in-training, Neito took an immediate liking to Hitoshi due to the latter's antagonizing of Class 1-A. Neito was happy that Hitoshi was willing to work on a team with him. He expresses empathy for Hitoshi, because like him, he grew up being derided for having a Quirk deemed unsuitable for becoming a hero.
Neito clashes with Izuku during the fifth round of the Joint Training Battle. Neito admits that he has to be on full guard since he's aware of Izuku's outstanding fighting technique. When they meet in battle, Neito tries to provoke him to respond, but fearing that he had copied Hitoshi's Brainwashing Quirk, Izuku remains silent. Beside this, Neito continues provoking Izuku, even to the point of sadistically taunting Katsuki in his involvement for ending All Might's career. Angered, Izuku aims his Air Force technique directly at his foe.
Before Izuku can ever release his attack, a mysterious black power bursts out of his arm and goes on a rampage. Thanks to the cooperation between Ochaco and Hitoshi, Izuku could be stopped, and the mysterious power controlled. Neito takes advantage of their guard being down and ambushes Izuku. He manages to touch him and therefore copy his Quirk, and then attempts to activate One For All against Ochaco, but it doesn't appear to work, allowing Ochaco to defeat him and lock him up.
Even though Class 1-B loses the match, Neito still retains his old demeanor. Neito begins to rant about how his team didn't lose in terms of substance and reveals his newfound knowledge relating to Izuku's Quirk. He implies that he could easily beat Izuku if they were to rematch. Despite his disrespectful and harsh attitude during the battle, Izuku does not seem to hold any grudge against Neito, in fact he was worried about him when he tried to use the One for All, fearing for his physical integrity.
The next day, while trying to find more out about Eri's Rewind to help Shota, Neito reveals aspects of One For All that Izuku himself doesn't know. Neito says that he couldn't use Izuku's Quirk properly because, just like Eri's, it requires stored-up energy to work, and as Copy can’t take that it isn’t possible for him to use it.