Protagonist of the series. She tends to be a little air-headed and easygoing. When her grandfather suffered a stroke her dad decided to move out to the countryside and take over the farm. Since Nao still had a semester of junior high school to finish, she convinced her parents to let her rent an apartment and live by herself, at least temporarily. Then she finds out with surprise that someone else had rented the same flat: Hisashi Uehara. The landlady suggests that Nao and Hisashi can just live together; this way, rent will even be cheaper, and so they do. At first, she did not notice that she liked Hisashi until she got a little counseling from her friends. She starts to date Hisashi later in the story. In the end of the manga, she and Uehara move into different apartments because the landlady of their previous apartment had a son who came back from America and had wanted to rent out a room for him and his girlfriend. When Nao agrees, she looks for other apartments for two and learns that Uehara wishes to live alone to become independent. Although at first shocked and upset, she respects his decision only to find out that the two now live next door to each other because of the help of the landlady of their previous apartment and Nakatsugawa.
A popular and good-looking guy, and unsurprisingly has a bunch of fangirls. In fact, he made the school's "Top Three Hottest Guys" for three years in a row. He lives together with Nao because of the whole renting fiasco. He's very aloof and antisocial, and gets straight A's without studying. Because he is very mature looking, he is commonly believed to be older than he looks. In Good Morning Kiss, it is stated that he looks a lot like his mother. Both of his parents died while he was still an elementary school student. He had had a big crush on Yuri for 6 years but was heartbroken when she had married his older brother despite her knowing about his crush on her. He then started to date Nao later in the story. He gets mad or jealous whenever Abe shows up out of nowhere or whenever he or any other boy hangs out with Nao. Continuing to give off the cold shoulder, he's outspoken and slowly lightens up after dating with Nao Yoshikawa. To make him confess that he liked Nao, in Chapter 15, Yuri hid Nao in her room and asked Uehara why he did not want to come home. He admitted that it was because he liked Nao, and that although his original reason for leaving home was because he was heartbroken from his older brother's marriage with Yuri, he has gotten over his crush on her and had wanted to be with Nao. Nao slipped down by accident, and he hears her. He tells her he really meant it after Yuri leaves, and does not get his feelings replied back to until Valentine's Day, when they officially become a couple. He lies about his age to get a job and has a surprisingly large appetite. In the end of the manga, he and Nao move into different apartments because the landlady of their previous apartment had a son who came back from America and had wanted to rent out a room for him and his girlfriend. When they agree, Uehara tells Nao that he wants to live alone because he wants to be more independent but tells her that they will never be apart. This ends up as a rumor that Uehara had proposed to Nao and had spread across the entire town. Uehara clarifies to Nao that he did not propose to her but wants them to still be together. When he and Nao move into their apartments, they learn that they live next door to each other because of the help of the landlady of their previous apartment and Nakatsugawa.
One of Nao's best friends, and very loyal. She is boy-crazy and is very knowledgeable when it comes to that. She also keeps a book of all the hot boys she knows. Although Marina is very knowledgeable about them, she says she would never go out with anyone she doesn't like. Later in the story, she starts going out with Mi-chan. Usually, once starting to date a boy, she breaks up with him shortly after. Her only serious boyfriend has been and is still Mi-chan. However, when she gets into a fight with him about her hair, she visits him with Nao's advice and sees him with another girl. However, the girl with Mi-chan was someone in his study group. Marina confesses that she knew Mi-chan was not cheating on her but feels insecure about their relationship because she worries that he will establish a new life at his new high school and that he will no longer have room for her and says she may break up with him. He waits for her to tell her that he does not want them to break up and she tells him she was only joking. He sighs with relief and Marina kisses his cheek, ending their fight. She also takes computer classes.
Nao's classmate, who they call 'Abecchi'. He is called the "King of Confessions" because he often goes around asking girls out, but gets rejected every single time. He wants a girlfriend so badly that almost any (cute) girl will do. When he was younger, he was friends with a girl who he saw as his girlfriend. However, when he hears that she becomes someone else's girlfriend, he asks her why and she tells him it was because he had never said anything, which is also why he confesses to random (cute) girls. Because of this incident, he warns Nao to be careful to not have misunderstandings between her and Uehara regarding their relationship. He asks out Nao, and obviously she rejects him. Despite that, Nao and Abe remain good friends. On the same Valentine's day as the day Nao had confirmed Uehara's feelings for her, he receives chocolate from a cute girl named Tsukasa Ooishi, who after becoming a couple with Abe, moves to England, then moves back four months later. Some of his later crushes are Nanako and Yuri. He also considers Uehara his best friend.
Nao's other best friend, also known as Mi-chan. He is the son of a doctor. He starts dating Marina later on in the series. He has loved Marina,as far as he has known. In one of the chapters, Marina thought that he was getting too busy with his school,(while everyone goes to Kubo High,he goes to a different high school because of sports)he once cancelled on a date because he had to study for exams, so Nao and Marina were shopping and Nao asked her to just visit him (on the same day their date had been cancelled). After Marina agreed, they reached Mi-chan's house just to find him coming down the stairs with another girl. Marina gets heart-broken and then leaves without saying a word upon seeing this scene. However, it turns out to be a misunderstanding, because when Nao questions Mi-chan about this, she finds out its just his study group. Nao talks to Marina about it and tries to explain to her that it was a misunderstanding, to which she replies by saying "Maybe I should just break up with him!" Upon hearing this, Mi-chan later makes-up with her when she comes back home from her computer classes and fins Mi-chan sitting on the stairs of her front door. When she asks him since when he was there, he replies saying that he went there right after his school was over(which was 5 hours)and then she asks him about what happened to his club and he says he skipped. This really touches her and she gives him a kiss on his left cheek. After this they make-up.
Hisashi's sister-in-law. She's young and pretty, and apparently Hisashi's had a crush on her for six years before she went and married his older brother. It was because of this that Hisashi had run away from home in the first place. Yuri is nice and carefree, and becomes good friends with Nao. She turns into a "kissing monster" when she's drunk (she's 21). She is also a shopaholic.
The twelve-year-old daughter of the owner of the shop that Hisashi works at. Although on the outside she is a sweet, angelic girl, her true self is that of a spoiled, selfish brat. She wants Hisashi for her boyfriend and loves to make fun of Nao. Luckily Hisashi is not so oblivious in this case and knows that she is two-faced. In the final chapter, she realizes that her feelings for Hisashi were nothing more than admiration and was not truly love.
He is the son of the owner of a ramen shop. Nao starts working there after getting into an accident on the road when he hits her with his bike(it was actually her fault because she was not concentrating on the traffic lights). His father was sick so he had to take care of the shop all alone. During the accident Nao broke bowls which were specially made bowls worth 13,000,000 yen (They later find out that they had been tricked since no bowls could be that expensive) given to them by their most rich and special customer, Nakatsugawa-Sama. They go to apologize to him and when they tell him, he says that the person who made them was a person he loved very dearly. At the same time Landlady-san, the owner of the apartment Hisashi and Nao live in, comes in and gives him new, handmade bowls. They find out that the 'Boyfriend' that she keeps mentioning is Nakatsugawa-sama and the bowls now get replaced by the bowls that she newly made for him. She was working for them in debt for the bowls and now she didn't need to so she leaves. Later she realizes that she can't work anywhere else so she comes back. When Seihi is at work, he has a really furious face but outside, he is really sweet and appears to have feelings for Nao. But in chapter 53, he realizes that it is just that he loves her as a sister.
Nao's friend upon entering university. She is a plain looking woman with glasses. She is single and often daydreams about what it would be like to be in a relationship with. Nao and Marina state that she and Abe would be a perfect couple for one another since they are alike in their daydreams about relationships. This causes Ota to blush and run away from Abe when she sees him, denying that she would never enter into a relationship with him.