During his adolescent years, Hizashi attended U.A. High with Shota Aizawa. While picking their hero names, Shota was unable to decide so Hizashi chose the name "Eraser Head" for him. Along with fellow class mate Oboro Shirakumo the trio became well acquainted. During his second-year, his friend Shota began to have doubts about his ability to become a hero. One day, Hizashi pointed out Shota gloomy demeanor arriving late and feeling powerless, and tried to cheer him up with bad jokes, joining him minutes later Oboro.
Class 2-A's homeroom teacher begans by reminding students that most second-years do Hero Work-Studies during summer vacation to get a taste of what the world of a Pro Hero is like. Hizashi along with Oboro and Shota were reminded they have yet to assign themselves to an agency. Hizashi and the rest of his class geared up for Joint Exercises with Class 2-B that consist of Battle Training, Rescue Training, and Entertainment Lessons. He excelled in each exercise.
A few days later, Hizashi's teachers discussed if he has any chance of landing an agency. His homeroom teacher considered he shouldn't have problems, because his Voice Quirk has implications in battle and entertainment, although he might be easily distracted, and have trouble given a set role. They could easily see him take on more than one profession in the future.
On one of the rooftops of the U.A. Hizashi was with his friends Shota and Oboro having lunch and discussing Work-studies, at the same time they talk about what they should do with a cat that Oboro brought to school. The third year student Nemuri Kayama showed up to talk with them and ended up adopting the cat.
After a period of practices, all students returned momentarily to the U.A. to show their progress in a Two on Two Battle Royale Training. Hizashi noticed Shota has added Oboro's signature googles to his hero costume, and Oboro jokes about it. Sensoji interrupted the conversation that they stole his eye protecting idea. At Oboro's suggestion, the teacher ordered to team up prioritizing the partnership during the Work Studies. Hizashi protested because that means he had to team up with Sensoji, but the teacher ignored his complaints.
The battle begans, and despite Yamada's grumbles, he made a good combo with Sensoji, defeating their opponents without problems. At the end, Sensoji-Hizashi team faces the Shota-Oboro team. Before the two duos went against each other, Sensoji demanded Shota to handed his googles over if they lose. Oboro accepted and wagered their googles against Hizashi and Sensoji shades. Hizashi asked why he is included in the bet. Sensoji ordered Yamada to stand back, because he planed to defeat them alone, but thanks to their great teamwork, Shota and Oboro managed to defeat him, winning the team battle. The wager is called off by Shota, causing Sensoji to storm off.
Later, Hizashi was hanging out with Shota and Oboro, with his new googles to match the other two. Oboro talked about the future and suggested that, when the three go independent, they should start their own agency. Hizashi and Oboro would start the combat and Shota would be the edge in battle to allow them the final blow. Shota told that he never agreed to a team-up with them two, which made both Oboro and Hizashi tease him and his broody act.
A week later, the students returned to their respective agencies to continue with the Work-Studies, and accordingly, Hizashi and Sensoji returned with the Buster Union. The team of heroes were notified that a villain known as Garvey was causing great destruction in the city, and the entire Buster Union team, including the two students, flocked to face him.
Once there, the team leader ordered to everyone to unleash the full power of their Quirks. All of them fired powerful attacks at Garvey, but to their surprise, the villain absorbed all the attacks. Before they could react, the villain strikes back using their own attacks against them, with even greater power. The wave of energy swept a large area, and Hizashi and the entire Buster Union team was defeated. With them out of combat, the Team Purple Revolution, of which his friends Shota and Oboro were part, fought against Garvey. 
In the end Shota was able to defeat the villain alone, but at a terrible cost: Oboro Shirakumo died in the confrontation. Even after his body was removed from the area and raining heavily, Hizashi and Shota remained for hours contemplating the place where Oboro died, mourning for the loss of their friend.
The Oboro’s death had a strong impact on both but specially on Shota. While Hizashi could, more or less, overcome his loss, Shota was isolated, barely socializing with his classmates and training most of the time to improve his combat skills. Only Hizashi interacted with him and many times he saw with melancholy how Shota overtrained.
Hizashi ended up graduating from the U.A. and start his career as a Pro Hero.
Months before he started working as a professor at the U.A., Hizashi was involved in a series of events caused by a criminal organization known as the Villain Factory, a criminal organization responsible for trafficking Trigger, an drug that boost Quirk but turns its consumers in violent Instant Villains.
One day, one of the Factory's agents, Kuin Hachisuka, uses her Queen Bee Quirk to inject Trigegr into innocent civilians, causing an Instant Villain Outbreak. Detective Naomasa immediately call for backup. Hizashi and other heroes appear immediately and quickly they suppress the outbreak.
Due to the villain outbreak, where several innocent people were turned into Instant Villains, detective Tanema organized a meeting in the Police Station with several of the heroes who helped to stop the outbreak, to discuss the situation the best action to take. Hizashi calls his friend Shota to tell him that he cannot attend the meeting because he has a cold and he must go to a doctor.
Weeks later, he is invited by Makoto to participate along with other heroes in a musical event organized by the Marukane. Present Mic accepts the invitation and acts as the announcer at the festival. After the introduction, he tells the audience that in the evening portion will begin with the ensemble's FeatherHats performance.
In the greenroom, he meets Midnight, who ask him where Eraser Head is. Present Mic replies that Shota told him he would come to the show if he can. Midnight assumes he won't come. Finally, Shota cannot attend because he has to face a villain that generates a blackout in the area. Fortunately, Makoto's team fixes the generators and the festival continues, ending up being a success.
Months later, on the occasion of the return of Captain Celebrity to the USA. Makoto decides to organize a farewell show at the Tokyo Sky Egg, inviting several of Japan's most famous heroes to the event, including Present Mic.
In the middle of the event, the Tokyo Sky Egg is attacked by creatures known as Bombers, commanded by the villain Number 6, a member of the Villain Factory. The main objective of Number 6 is to kill Captain Celebrity, and to achieve it he orders the bombers to damage the structure, leaving the Captain celebrity at his mercy by having to use his strength to prevent the building from collapsing, leaving him completely defenseless to the Bombers attack.
The heroes who were participating in the event decide to organize in two groups: one group goes outside and confronts the enemies, while another group helps the show staff to look after the spectators who had come to enjoy the show without telling them the truth about what is happening, to avoid panic. Present Mic is part of this last group. Thanks to the intervention of the heroes, and the timely arrival of All Might, they manage to avoid a tragedy.
Weeks after the Sky Egg Bombing, Midnight phones Shota Aizawa to talk about her experience as a teacher at the U.A. and tell him that Hizashi Yamada will start teaching next semester, and the only one missing is him. Shota replies that he has not agreed to being a teacher, but Midnight replies that according to Present Mic he only needs a good shove to take action. Although Shota is annoyed by Hizashi's comments and Nemuri's insistence, after re-thinking, he accepts the offer to be a teacher.
Present Mic first appears at U.A. High to introduce and explain the rules of the Entrance Exam to the candidates. He surprises the students when he returns to announce the practical exam's start and end.
Following the practical exam, Ochaco Uraraka tries to negotiate with him about transferring her exam points to Izuku Midoriya, who saved her life during the practical. Hizashi explains to her that Izuku doesn't need her points because he scored more than enough rescue points to pass himself.
Once the media finds out All Might is teaching at U.A., they storm the school looking for a quote from the number one hero. They somehow bypass the school's defenses and get on the property, prompting the alarms to sound. Hizashi and Shota both try to get the media off the property but they refuse to leave. Hizashi suggests they beat them up for trespassing, but Shota warns him to stand down and wait for the police to arrive.
Present Mic arrives at the U.S.J. with the other faculty members after Tenya Iida calls them to help save Class 1-A from the assault by the League of Villains. He uses his Quirk to subdue several of the villains and rescues Fumikage Tokoyami and Koji Koda.
Present Mic acts as the main commentator and announcer for the U.A. Sports Festival. He manages to talk Shota into commentating alongside him. During the opening ceremony for the festival, Present Mic announces every class that's taking part one by one. After Midnight introduces herself as the chief referee, the Obstacle Race is announced to be the first event. Midnight explains the rules and the event begins as Present Mic gives a play by play to the audience. Hizashi reveals the first Obstacle will be a blockade of villain bots he nicknames the "Robo Inferno". After Shoto Todoroki freezes a gigantic villain bot on his own, Present Mic commends him and reveals to the audience that he was a student let in on recommendations.
Present Mic explains the second obstacle is "The Fall" once the students reach it; if they fall, they're out. He mentions that it can be difficult to become a popular hero without a flashy Quirk to tease Shota. He also comments on how easily Shoto is getting ahead and that Tenya looks foolish crossing the fall. Once Shoto reaches the third obstacle, the "Minefield", Present Mic explains that it is the final obstacle and the mines aren't that powerful.
Present Mic continues giving a play by play of the race, including an excited take on Izuku's sudden pursuit of first place. He notices Shoto and Katsuki stop fighting to pursue Izuku and comments on how Shota's students are amazing. When Shota credits them for their own will to succeed, Present Mic teases him by calling him a terrible instructor. To conclude the event, Present Mic announces Izuku Midoriya as the champion and asks the crowd to cheer for all the competitors as they prepare the results.
Just as the Cavalry Battle is about to begin, Hizashi wakes up Shota in preparation for the battle royale. At the beginning, Present Mic comments on Team Mineta's clever use of Mezo's body to cover both Minoru and Tsuyu. He's excited to see Katsuki attack Team Midoriya in mid-air, but questions if leaving his team is even allowed in the event. When he decides to take a look at the rankings seven minutes into the event, Present Mic is surprised to see Class 1-A isn't doing well. He announces the halfway point of the game and ponders what will transpire next. 
When Team Todoroki freezes the other teams, Present Mic is impressed with Shota's comments on Shoto's strategy. With only a minute left in the battle, Present Mic comments that Team Midoriya has miraculously kept away from Team Todoroki for the latter half of the games. He's also taken by surprise when Tenya uses his Recipro Burst technique to steal Team Midoriya's points in an instant. Present Mic comments on all of the shake-ups within the final minute, including Katsuki's merciless assault on Team Monoma. He announces the end of the second round and all four of the qualifying teams. Afterwards, he asks Shota to grab lunch with him, but he refuses so he can take a nap.
Prior to the final round, Present Mic announces that those who didn't make it can enjoy the cheerleaders and recreational games. He and Shota are both surprised to see the girls of Class 1-A are dressed like cheerleaders as well. He also explains that the finals will be a one-on-one fighting competition. When Nirengeki and Mashirao drop out of the finals, Hizashi calls it a strange turn of events. Present Mic announces the beginning of the finals and introduces the first match between Izuku and Hitoshi Shinso.
At the start of their bout, Present Mic comments on how Hitoshi immobilizes Izuku using their Quirk. He's surprised to see how Izuku listens when Hitoshi commands him to walk out of bounds, and even more shocked when Izuku breaks his mind control. When Izuku throws Hitoshi out of bounds and wins the match, Present Mic says the match was kind of boring but still asks the audience to applaud both participants. He announces the next match and introduces both Hanta Sero and Shoto. He commends Hanta for his strong start but is silent and staring with awe after Shoto completely freezes Hanta along with half of the stadium.
The battles resume after all the ice is removed and Present Mic introduces the next two competitors: Ibara Shiozaki and Denki Kaminari. He introduces Ibara as an assassin, but she takes exception to this and questions why he did so. Present Mic apologizes and is annoyed when Ibara starts monologuing over her own humbleness. She defeats Denki rather quickly, prompting Present Mic to comment that it was over in an instant. He continues on to the next match between Tenya Iida and Mei Hatsume, but is dismayed when Mei turns the match into a commercial for her gadgets. He commentates during Mina's match with Yuga, Fumikage's battle with Momo and Eijiro's fight with Tetsutetsu. He mentions that Eijiro and Tetsutetsu's Quirks are redundant and even gives them the same introduction for their match. They fight to a draw, and while they recover Present Mic announces the last match between Katsuki Bakugo and Ochaco Uraraka.
During the final match of the first round, Present Mic makes it evident he's rooting for Ochaco. He becomes concerned when Katsuki barrages her with explosions and agrees with the crowd when they start booing him for it. However, Shota takes it upon himself to hit Present Mic and reprimand the crowd for their negativity. Hizashi is surprised when Ochaco reveals her strategy and drops floating debris from the sky. He's equally shocked when Katsuki blows it away with a super explosion. When the match ends, Present Mic calls the outcome depressing and announces that there will be a break between rounds. Before the second round's first match, Present Mic comments on the huge anticipation for the epic battle between frontrunners Izuku and Shoto.
Present Mic announces their match closely, commentating on Izuku's counters against Shoto's ice. When Shoto unleashes his flames and Endeavor yells across the arena, Hizashi hesitantly comments about how much of a good father he is. The match concludes with a gigantic explosion that Present Mic questions. Shota explains that the arena's air had been cooled then rapidly heated, prompting Hizashi to realize that is what caused the explosion.
Hizashi continues to announce the rest of the second and third rounds leading up to the final matchup between Shoto and Katsuki. Shoto opens the match with another giant ice blast and questions whether the match is already over. However, Katsuki tunnels his way out of the ice and surprises Hizashi and the viewing crowd. He commends Shoto's use of an ice wave and mentions that it looks like fun. Come the battles climax, Present Mic comments on Katsuki's Howitzer Impact technique and that Shoto refused to use the fire blast he used to beat Izuku. Afterwards, Present Mic announces the conclusion of the U.A. Sports Festival.
In the faculty room, Hizashi and Shota are both annoyed by All Might's obnoxious ring tone.
Present Mic attends a meeting with his fellow faculty members to discuss changing the final exams. He questions whether having the students fight teachers in pairs is a good idea because it may be difficult to grade them if they are easily defeated. He and the other teachers meet with the students prior to the practical exam so Principal Nezu can explain the change. He comments that it differs from combat training because the students will be up against superior fighters. Kyoka responds with confusion, claiming that Present Mic is just an announcer. This irritates him and he yells for Kyoka to have some respect. Present Mic is placed against Kyoka Jiro and Koji Koda to drown out their sound related Quirks.
Present Mic begins their battle guarding the escape gate and uses his loud Quirk to blast the entire forested area with his voice. As he waits for them to draw closer to the escape gate, Present Mic continues to yell and flood the forest with his voice. Kyoka manages to counter one of his shouts with her own Quirk, but Hizashi is unimpressed with her power.
After yelling for them to come out for a few more moments, Present Mic notices bugs coming from underground where sound doesn't travel well. He is paralyzed with fear and allows the bugs to crawl up his leg, causing him to faint and allow Team Kyoka and Koji to pass through the escape gate.
Present Mic is later seen among other U.A. teachers in an emergency meeting regarding the villain attack at the training camp and the capture of Katsuki Bakugo. Present Mic pointed out how the time of peace had made them soft and was the one to bring up the idea of a traitor in U.A. He desired to find the identity of the traitor, only for his theory to be dismissed by Midnight and Snipe.
Present Mic and Eraser Head's substitute All Might were assigned to monitoring Shoto and Katsuki at the Second Provisional Hero License Training training. He explains that Shota is busy dealing with tasks related to U.A. High School. Shoto inquires, causing Present Mic to explain that his Quirk is needed to help the rescued girl, and for that reeason, he ask him to come along as a bodyguard. All Might further comments that Present Mic's presence is a precaution in light of the League of Villains' movements.
Shoto, Katsuki, All Might and Present Mic take the bus to the Provisional Hero License Training centre. All Might and Present Mic prepare to go and watch from the bleachers, but unexpectedly encounter a furious Endeavor who, although thanks All Might for looking after Shoto, demands a chat with the former Number One Hero. Seeing the situation so tense, Present Micdecides to buy coffee for all three.