Nanami Haruka (七海春歌 Nanami Haruka) is the only controllable character and is the heroine of Uta no☆Prince-sama♪. She enters Saotome Academy in the hopes of becoming a music composer so that she can write songs for her idol, HAYATO. In the anime, she is voiced by Sawashiro Miyuki (沢城みゆき Sawashiro Miyuki).
She is a shy, honest girl, shown to be rather restless and possesses an optimistic personality. Whenever she is unlucky or having a bad day, she remains confident. She's a very hard-working girl who has an ability to move people's hearts. She has been dubbed as the Goddess of Music by Tsukimiya Ringo and Shining Saotome because of her composing and ability to create beautiful music. She is rather naive and a klutz, but she makes up for it with her perseverance and her efforts to become a great composer.
As a child, Haruka had poor health, so her parents decided to send her to the countryside to live with her grandmother. There, she eventually learned how to play the piano, but never actually learned how to read music.
This was a plot device created to prompt Masato and Otoya's episodes in the anime. In the game Haruka knew how to read music and did not have any difficulty with this.
Once she returned to the city, her health began to fail once more due to the amount of people and pollution. While she was panicking, HAYATO appeared on a big screen, his music flowing through the air, calming her down. Her new goal then was to compose a song for HAYATO to sing, so she applied to Saotome Academy.
Haruka is late for the entry exam at Saotome Academy for young musical talents and due to her tardiness, the guards didn't allow Haruka passage. Otoya helps Haruka out, as well as Ren. It is revealed that she was late because she helped a lost child find her mother. Despite Otoya and Renprotests against not allowing Haruka in, the guards of the school would not let her in.The headmaster arrives and tells the security guards to let Haruka take the test. She is accepted into the school. When unpacking that night with Shibuya Tomochika, a black cat jumped into their dorm room through the window. Grabbing Nanami's handkerchief, it ran back out the window. Frantically, Haruka followed it. After retrieving it, Haruka saw Tokiya kneeling by the gazebo, and mistook him for HAYATO.
When Haruka asked if he really was HAYATO, Tokiya responded coldly, saying not to get him mixed up with his twin brother. Shining Saotome then jumped out of the bushes, exclaiming that Tokiya was HAYATO's younger twin brother, and Haruka returned to her dorm. On the first day of classes, Otoya finds out they are in the same class, and is then paired up with her to create a song. It is revealed in class that she is unable to read music, and runs out crying. Later on, Otoya and Tomochika find her and console her, telling her to do her best. She spends the rest of the day in the library learning how to read music. Otoya finds her humming a theme outside, and finds inspiration from it to finally create some lyrics. They then ace the assignment with high scores.
The next day, she comes in seeing the chalk board littered with slander against her. Otoya and Tomochika run in and erases it. She is again asked to play the piano, but the pressure and the whisperings from her fellow students causes her to freeze up and run out again. After school, Haruka practices the piano, hoping to get over her fear. However, when she tries to play, she realized that she could not bring herself to move her fingers. While her hands are immobilized by fear, Masato appears and starts playing the song 'Twinkle Twinkle Little Star' on the piano. Haruka then joins in and is able to play the piano with ease.
Later, she finds out that Ren is about to be expelled due to not handing in any assignments and skipping class, and encourages him to try to write some lyrics. Ren tries, but after being confronted by Masato, gives up and rips his lyrics in pieces, scattering them throughout the school grounds. Haruka tries her best to get them all back, and Tokiya notices her doing this. Ren is touched by Haruka's efforts, and decides to finally sing a song to save himself from being expelled.
They meet at the day of the entrance exams, and from there on out, Otoya has been very kind to Haruka. They were paired up to create a song, and together they achieved one of the highest scores. He is also one of the six guys who requests her as their partner for the graduation audition. Later on he is grouped with the other five into a new group called ST☆RISH, due to Haruka not being able to choose between them, and crushing five of their dreams. It has been revealed that he has had a crush on her for quite some time, though it was never shown exactly in the anime. In the second season Otoya express his happiness of being able to live in the same place as Haruka but is soon reminded that he can't have a romantic relationship with her. During Episode 5 of the second season he is seen to be overjoyed at being in the haunted house with Haruka and blushes when she gets scared and holds his hand. In the same episode he nearly confesses his love for Haruka but they both get scared and stops Otoya from speaking.
Syo sees Haruka as a friend because of her encouragement for him looking up to Hyuga Ryuya. Like the others, Syo also puts his name down to be Haruka's graduation partner. In the second season it looks like he and Haruka have been very friendly since Syo seems to have lent her one of his favorite movies and when she tells him that next time she will give it back to him he lets her keep it as a present. Also in Episode 3 of the second series, Syo thanks Haruka for helping him with his audition after he saves her from falling. He then gives her his favourite hat, showing how much he trusts her. And upon giving her this hat, he tells her that he will start up a fan club for himself and Haruka says she will join.
Cecil is The prince of Agnapolis who was cursed and turned into a black cat. In the anime, he was the cat that Nanami Haruka is taking care of, she named it Kuppuru (meaning black and fluffy). In the anime, he said that his country is from the far west. Haruka cares for Cecil because he was the cat that she took care of, and they are usually seen together when Haruka is alone or depressed. In the second season, he tells her that her songs saved him and he confesses his love for her, much to the other boys' dismay, but since romantic relations aren't allowed, he tells her that he'll always be by her side and desires to only sing the songs she writes for him.
Haruka idolizes him because his song, Nanairo no Compass, saved her and motivated her to become a composer. Although at the start of the series, it was told that Hayato was Ichinose Tokiya's twin brother, it is later revealed that they are one and the same person.
The first time they meet, Haruka convinces herself that Tokiya is HAYATO, but her belief is crushed when she hears that Tokiya is not HAYATO, but rather his younger twin brother. Tokiya has paid a lot of attention to Haruka ever since they first met. Tokiya got confused numerous of times of why Haruka always tried her best. After Haruka knew his true identity, Tokiya distances himself from her. But his heart is softened by Haruka's kindness when she states that she wants to hear his songs. Tokiya surprised, finally realizes that he can start from the beginning again and that he will try singing. Ever since then, he saw Haruka differently.
Masato is first introduced at the start of class, but has actually seen Haruka before, singing with a group of children in a playground. Seeing her sing so happily inspired him to pursue a career as an idol. After Haruka freezes up in front of the class, Masato goes after school to help her get over her fear. He is one of the six to request her as his partner for the graduation auditions, though he did his via a letter in her locker. In the second season Masato is cleaning Haruka's room when she comes in. After saying hello, Masato thinks of how he has been having some strange feelings towards Haruka and wishes to stop them.
She seems to be on friendly terms with him because Natsuki likes Haruka since she is cute and very hard working. She also once said that she loves basking in the sun just like Natsuki's dog, Elizabeth, therefore Natsuki feels happy about what she said that day. In the second season Natsuki finds himself really happy about living near Haruka.
They met at the day of the entrance exams, and from there on out, Ren has been very kind to Haruka because he saw her help a lost girl find her mother. Therefore, she got the nickname "Little Lamb." Like most of the girls, Ren treats Haruka kindly and thinks that she is nice because she helped him once. In the second season, Ren expresses his happiness of being able to work together again by giving her a lot of roses he grew which he named after her.