Misaki is only seen at Seiyo Academy which means she has the typical girls' uniform: a red plaid skirt, a blazer with a red tie and white shirt, and white socks pulled up so they are below her knees with pink shoes. On the left side of face in her hair, she has a yellow and purple clip pulling back her bangs. She also has her hair pulled up into two ponytails, the right one shorter than the left and two braids sticking out under her ponytails on the back of her head. Her eyes are a shade of brown.
Misaki is described by many as a hyper girl. She tells Amu that a lot of people didn't like her for that reason, but was happy when Tadase told her that he admired how she was always in high spirits, those words beginning Misaki's infatuation with him. She has a crush on Tadase as many of the girls at the academy do, and knows a lot of his information shown when she asks Amu if she knew anything about him. When Amu says she didn't, Misaki told her some things, like his position in the Guardians (King's Chair), his birth date (March 29), his zodiac sign (Aries), and his blood type (B).
She befriends Amu and tells her about her crush so the two could team up and get rid of his rivals. When Amu asked why Misaki had chosen her, Misaki replied saying she thought Amu was safe since she had been rejected by Tadase in front of the entire student body, making Amu relive part of the past she had wanted to forget.
Misaki doesn't particularly like Saaya as she was the president of the Tadase Fan Club, some rivals of Tadase's affection according to Misaki. She tells Amu that Saaya and her club are enemies to be feared since they would try to challenge them. But, she says, their true enemy was someone else, someone Amu couldn't believe Misaki would point out: Nadeshiko. She claims that Nadeshiko is deceiving Tadase having already been given the advantage of being the Queen's Chair, though Amu tries to tell her otherwise.
Calling their joining the Misaki & Hinamori Amu Alliance, she sets out to capture Nadeshiko, Amu trying to pull her back, but they both run into Tadase. He walks over to them and talks, but Misaki gets shy and hides behind Amu before they both run off. Alone, Amu tells her she fell apart when she wasn't supposed to, so Misaki tells her that even though Amu was a Guardian, she was no help. They laugh over their silly arguement and the next day, Misaki has a new plan for them: a secret love charm. When she and Amu find Tadase to have him write his name on the paper, she doesn't fall apart like last time and asks him to sign; he obliging without questions. As he was signing she called him "prince", saying he was pretty, not knowing that that was the "taboo" word for him.
While Amu went to go straighten him out, Saaya finds Misaki and tells her that Tadase didn't like hyper girls. She doesn't let it get to her and leaves, seeing Tadase with Nadeshiko. She hides, but overhears him say he didn't like being so high strung when he Character Changed. She asks him about it what he had said about being high strung and how he didn't like it and when he doesn't deny it, she runs off with tears. Misaki is walking by herself thinking how she would never get a guy like him because of her hyperness, causing her heart's egg to get glazed over with gray. Nikaidou happens to see this while Amu is looking for her. She finds Misaki standing by herself before an X-Egg appears. An X-Character hatches and Misaki falls to the ground.
Amu, while running away from it, notices that the X-Character's attacks were hyperactive. She falls into Tadase who had Character Changed and blocks the attack, telling her to Character Transform. She unlocks her heart and becomes Amulet Heart. Amu moves toward the Character when a transparent picture of Misaki appears and says that no one would like a hyper girl like her. Amu tells her not to doubt what makes up who she was and said she liked Misaki the way she was. Amu locks onto her negative heart and uses Open Heart to get rid of the "X" on the X-Character. Misaki's Guardian Character appears and tells Amu that Misaki's dream was to get married to the person she loved and to be happy.
She throws her little bouquet of flowers at Amu, who catches them, and bids her a goodbye before going back to her egg and into Misaki. She wakes up and Amu tells her there was nothing wrong with her. Tadase chips in and says he thought it good for a girl to be full of energy. Misaki grabs Amu and pulls her off to the side thinking that what he said meant he liked her, but Amu asks her how she got that out of what he had just said. Misaki says she used her ears and Amu insults her, but Misaki pretends she didn't hear it while Tadase smiles from where he was standing.
While Misaki is walking and chanting "Hinamori Amu is my favorite!", she runs into Kukai. A scene similar to what happened between Misaki and Tadase takes place and Misaki has found a new crush. The next morning Misaki meets up with Amu to tell her she thought Kukai was cool and that the only problem was Yaya who was "definitely after him." Yaya comes and greets Amu, causing Misaki to attack her the way she first attacked Amu. The Tadase Fan Club minus Saaya are looking at Misaki from behind a bush, congratulating Saaya because Misaki had given up on Tadase, but when they turn to her, they see she is angry, wondering how Misaki had figured out Saaya had actually liked Kukai.
She also appered in the speech contest cheering for Amu.
- Tadase Hotori: Before she met Amu, Misaki had met Tadase and, after a few kind words of his, develops a crush on him. She gets Amu to join together with her to get rid of any potential rivals, the biggest to her being Nadeshiko Fujisaki. She gets a llittle depressed when she overhears that Tadase didn't like high-strung people, but when he tells her about how good it was to be full of energy, her crush is back and she thinks he had one on her, too.
- Amu Hinamori: Initially, she only befriended Amu because she wanted Amu to help her get rid of competitors for Tadase's affection, but is shown warming up to Amu as she chants "Hinamori Amu is my favorite." Amu warms up to her, too, telling her when wakes up after getting her heart's egg back that she liked her the way she was.
- Saaya Yamabuki: Misaki doesn't like Saaya since she was in charge of the Tadase Fan Club (some more rivals), and maybe also because she is rude, shown after Misaki yells at her when Saaya tries to put in her mind that Tadase could never like her. They do have similar taste in crushes since both liked Tadase and Kukai at some point.
- Kukai Soma: A scene identical to what happened between Tadase and Misaki happens between him and Misaki, causing her to have found another crush. She tells Amu this and says that the only problem was Yaya Yuiki as she was "positively after Kukai" and tries to attack her in a similar way she tried to attack Amu.