Momo Yaoyorozu was born into a rich family, and with a powerful Quirk. Due to the vast wealth of her family, she had access to various objects to study and practice within her home as a child, with the Russian matryoshka dolls being her favored tool for Quirk training. Having gained entry to U.A. High through recommendations, Momo Yaoyorozu attends the first day of school with Class 1-A. Their homeroom teacher Shota Aizawa immediately brings the class to the training field for a Quirk Apprehension Test and claims that whoever comes in last will be expelled. Momo manages to score first place in the entire class while Izuku Midoriya comes in last. Shota then reveals that he was lying about expelling the last-place student to make sure the students did their best. Seeing everyone's shocked reaction to the news, Momo tells them she's surprised they didn't realize that earlier and says she should have mentioned it. Momo answers one of Present Mic's questions in English class the next morning. That afternoon, Class 1-A participates in combat training for their Hero Basic Training class taught by All Might. They meet him at training ground beta after changing into their hero costumes. He splits them up into teams of two and has them simulate a hero versus villain situation. Momo ends up paired with Minoru on Team C. Following the first battle trial, All Might states Tenya Ida was the best in the battle despite his team's failure. He asks the students why this is the case and Momo responds. She replies that Tenya embraced the spirit of the trial while Ochaco let her guard down, Izuku rendered himself helpless and Katsuki's judgment was clouded by a grudge. She goes on to say that she and her classmates must devote themselves wholeheartedly if they wish to become Pro-Heroes.

The next day in homeroom class, Shota tells the class they need to choose their Class President. The class follows Tenya's suggestion of voting for the president and Momo gets the second most votes behind Izuku. To her dismay, she is made Vice-President while Izuku becomes the Class President. However, when it comes time to decide who the Class Officers will be, Izuku decides to give his role to Tenya. This leaves Momo discouraged because she still believes that she should be the representative. Later on, Shota announces to the Class that they will partake in rescue training at an outside facility. During the bus trip to the aforementioned facility, Momo tells Ochaco that the argument between Katsuki and others is too vulgar. Class 1-A arrives at the Unforeseen Simulation Joint, where they meet the Space Hero: Thirteen. Thirteen explains she developed the U.S.J. with the focus on training future heroes on using their Quirks to help others. Suddenly during Thirteen's speech, real villains invade the facility through a warp gate. Shota fends off the villains on his own and leaves Thirteen to evacuate with the class. They prepare to escape, but they are cut off by the villain Kurogiri. Katsuki and Eijiro attack him, but end up dealing no damage. Kurogiri responds by warping the class to the various areas in the facility. Momo is warped to the Mountain Zone along with Kyoka and Denki. She uses her Quirk to create a metal staff for herself and a sword for Kyoka to defend themselves.

While they're surrounded by villains, Denki mentions that he cannot shoot out his electricity or else he'll shock the girls too. Annoyed, Kyoka kicks him into a villain so that he can electrocute them. Another villain tries to get the jump on them, but Momo uses her Quirk to trap him in a net and he falls into Denki's electrical field as well. Momo creates a sheet of insulation to protect herself and Kyoka. She tells Denki he can attack without restraint and so he blasts the villains with an electric attack, and ends up destroying most of Momo's shirt. Kyoka points this out, but Momo replies that she can simply make new clothes. Denki's Quirk renders him helpless after he overuses it, leaving him open to an electric villain hiding underground. He warns Momo and Kyoka to surrender and threatens to kill Denki. Momo notices Kyoka trying to distract him while using her Quirk, but he quickly becomes wise to her act. Before it's too late, the trio is saved when the Pro Heroes arrive at the facility. Snipe uses his Quirk to shoot the villain multiple times to free Denki.[10] Then Ectoplasm arrives to escort the students out and take the villains into custody. Afterward, Detective Tsukauchi takes Class 1-A back to U.A. High. Two days after the attack on the U.S.J., Momo and her classmates return to school to discuss the attack. After Shota returns to class, the students get lectured about the importance of the upcoming U.A. Sports Festival. Momo mentions that she's excited about the opportunity to get scouted. For the next two weeks before the festival, Momo trains by reading up on the molecular structures of the items she can create. The day of the U.A. Sports Festival arrives and Momo changes into her P.E. clothes and prepares with her classmates in their designated waiting room. Like the rest of her peers, Momo takes notice when Shoto challenges Izuku.

Chief referee of the Sports Festival: Midnight announces the preliminaries will be an Obstacle Race four kilometers around the stadium, which immediately begins after the rules are explained. The students begin the race jam-packed inside a narrow corridor. Shoto freezes the tight space and gets out to an early lead, but Momo and others use their Quirks to avoid it. They all reach the first obstacle, which is a blockade of giant villain bots. Momo uses her Quirk to create a cannon and effectively shoots all of them down to clear the path.[15] After reaching the minefield, Momo is attacked by Minoru, who uses his Quirk to stick to her back and piggy-back on her all the way to the finish line. She finishes in seventeenth place while carrying Minoru against her will. After completing the race, she tells him that he is the worst. This qualifies them both for the second event: The Cavalry Battle. Shoto chooses Momo for his team along with Denki and Tenya. He tells Momo that her role on the right-wing provides insolation and defense for the team. She creates skates for herself and Denki so that the team can move very quickly and take advantage of Tenya's speed in the front of the formation. Towards the middle of the event, Team Todoroki confronts Team Midoriya for their ten million point headband. They attack Team Midoriya at the same time as many other teams. Shoto orders Momo to ready her Quirk to protect them from Denki's lightning. She also creates a stone staff for Shoto to use. Denki electrocutes the other teams and Shoto uses the staff and his ice powers to freeze them all in place.

Fumikage was able to defend against Denki's attack, giving Team Midoriya the chance to flee. Team Todoroki proves to be too fast for them to get away. Fumikage attacks with his Dark Shadow to stop their pursuit, but Momo defends Shoto by creating a block of stone to impede Dark Shadow's attack. Team Todoroki corners their opponent, but Team Midoriya is able to keep away from them by exploiting Shoto's weakness and keeping to his left side. With only a minute left in the competition, Tenya decides to use his Recipro Burst technique to steal the ten million point headband. In an instant, Shoto grabs the points by using Tenya's burst of super speed. Although, it renders the team immobile afterward since Tenya's engines become stalled. Team Midoriya attacks in a last-ditch effort to get their points back but ends up grabbing the incorrect headband. Momo mentions that they mixed up the headbands knowing Team Midoriya would underestimate them. Once the Cavalry Battle concludes, Team Todoroki finishes in first place and all their members move on to the finals: a one on one fighting tournament. Tenya apologizes for nearly costing them the competition, and Momo encourages him by saying he's the reason they won at all. Prior to the finals, all the participants are allowed an intermission for recreational games and rest. Momo goes to get food with Kyoka and they're both told by Denki and Minoru that they must dress up as cheerleaders for the cheer battle. Momo believes them and makes cheerleading outfits for the girls in Class 1-A, but this turns out to just be a prank from the boys. Momo yells at them and then falls into dismay for falling into their scheme.[21] Midnight calls all the students to draw lots for the fighting matchups and Mashirao suddenly decides to withdraw from the tournament, surprising Momo and others. He explains that he was simply Hitoshi's puppet and doesn't wish to advance, and he also questions why the girls are dressed like cheerleaders.

Momo and the girls are embarrassed by this. Momo ends up matched up against Fumikage for the sixth battle. Fumikage promises to give it his best, which Momo appreciates. During the recreational games, Momo reluctantly cheers with the other girls. The first round's sixth fight eventually arrives and Momo takes the stage to face Fumikage. She is visibly nervous for their bout since Fumikage's Quirk allows him to effectively attack and defend. She ponders over a strategy to defend herself by creating a shield, but she's interrupted when the battle suddenly starts. Fumikage calls Dark Shadow to attack immediately and Momo blocks it with a shield just like she planned. She tries to follow up by making a weapon, but Dark Shadow keeps pressuring her by attacking her shield repeatedly. She's unable to focus on her Quirk until Fumikage mysteriously stops attacking. Momo creates a metal staff and prepares to counterattack until Midnight points out that she's pushed out of bounds. Fumikage is named the victor in the quickly ended bout, greatly disappointing Momo. Momo watches the rest of the matches from the stands alongside her peers. She and Mina wonder why Fumikage is put on the defensive during his battle with Katsuki since he defeated them both so easily. After Katsuki wins the Sports Festival, Momo joins her peers for the closing ceremony.

Momo is a very prudent, dedicated person who is a natural leader. She is levelheaded and calm in dangerous situations, but she isn't above falling into a panic. Momo is very kind, polite, and relatively reserved, yet she can be blunt with her comments about people's mistakes and miscalculations, tending to be very direct and wishing to help her peers improve enough to become great heroes, such as when she tutored her classmates at her home. Momo shows further development as a selfless hero who gets inspiration from others while also taking the role of a leader in her class, thanks to her skills and intelligence. Because of her wealthy upbringing, she has a sensible and respectful attitude toward others, often being discouraged by discourteous behavior. Momo typically takes adverse situations in stride, expressing little concern for losing most of her clothing in battle, as she knows how to construct another set and would have made her costume even more revealing were it not for restrictions on exposed skin in a costume. However, this often makes others think of her as an exhibitionist. Ironically, she is relatively innocent and sensitive to vulgarity and rude mannerisms, constantly frustrated by sexual advancements from Minoru Mineta and Katsuki Bakugo's crude attitude. This innocence shows that she has a somewhat casual, natural, and non-lewd view toward nudity, which explains her lack of modesty in her costume.

While initially confident in herself, Momo's pride was crushed after her rapid loss to Fumikage Tokoyami at the U.A. Sports Festival and the comparisons she made between Shoto Todoroki and herself, starting to lose confidence in her ability to make quick choices on practical situations. It was further damaged during Uwabami's shallow internship, believing the heroine chose her despite being "an unworthy student" and tried to find more profound lessons to reassure herself. Thanks to Shoto's encouragement on their final exams, Momo regained confidence in her quick thinking, learning that people have different skills and can sometimes complement each other. Even when weakened and trapped by her opponents, she doesn't give up and shows an increase in her Quirk output, ultimately defeating her enemies. During her battle against Itsuka Kendo, Momo reveals that she still has doubts when comparing herself to others but doesn't let them interfere with her resolve, remaining confident and capable in the face of others. Momo becomes upbeat and eager when excited about spending time with her friends or helping them. She also tends to reveal how rich she is accidentally, yet most people understand she doesn't do this out of arrogance or malice. Despite her mature mannerisms, she occasionally finds herself roped into silly situations such as cheerleading, although she rarely expresses much enthusiasm.

Momo is a beautiful teenage girl. Momo is fifteen years old. Momo stands at a height of one hundred and seventy-three centimeters. Momo is fifteen years old. Momostands at a height of one hundred and seventy-three centimeters. Momo has long black hair that is usually tied in a spiky ponytail with a large lock hanging down on the right side of her face. Momo has short black eyebrows. Momo has black eyes. Momo has fair and smooth skin. Momo is wearing a tight, sleeveless, high-necked crimson leotard. Momo has a large, shapely bust. Her breasts have a round, high shape. Momo has a slim, narrow, and well-defined waist. Momo has wide, rounded hips. Momo has round, shapely buttocks. Her buttocks have a good size, standing out naturally and high but not being exaggerated. Momo has horrible, wide thighs that maintain a soft appearance. Momo's tight crimson leotard has silver lines on her waist and around her arms. Momo's crimson leotard is open to expose her skin from her neck to just below her navel. The crimson leotard's opening also has a deep chest slit that extends to her abdomen. Momo is wearing a tight yellow miniskirt that barely covers her butt. Momo's tight yellow miniskirt barely covers her butt. Momo is wearing tight red high-heeled boots. Momo's red high-heeled boots reach up to her calf, which dip sharply in the middle. Momo wears two golden tool belts around her waist, with the back holding her composition information books, and another thinner one around the top of her chest, below her shoulders. The design choice of Momo's tight crimson leotard allows her to create items from as many points on her body as possible.

Creation: Momo's Quirk gives her the ability to create any non-living material/object from her exposed skin by transforming the molecular structure of her fat cells. To create something, she needs to understand the molecular structure of what the material/object is made of. The more Momo eats, the more material she has to work with, so she needs considerable food ingestion for her Quirk to be effective. However, it takes her a more extended period and more skin exposure to create large objects, to the point where she forces large objects through her costume, leaving it shredded, though she claims she can repair it. This aspect of Momo's Quirk is likely the reason for her slim figure, as she constantly burns her fat to create objects. It is also possible that this is a significant weakness because if she generates too much without replacing her calories, she can become weak and anemic. As part of her training, Momo consumed large amounts of food to increase her Quirk's efficacy and reduce the time needed to create objects. Electromagnetic Rail Gun: Using her Creation Quirk, Momo summons a giant railgun, and Denki Kaminari uses his Electrification Quirk to power it, propelling a projectile to high speeds, shooting their opponent. Yaoyorozu's Lucky Bag: Momo creates a large cannon, which can launch a bag full of items. These items can be anything that she can make with her Quirk.

Her favorite thing is reading, especially encyclopedias. Momo has not yet had her first kiss and has not had a boyfriend either. Momo keeps her oral virginity, anal virginity and vaginal virginity intact.