Throughout the series Yuuka is shown to be a relatively smart and intelligent girl with a short temper. She gets angry easily, but is loyal to her friends and is friendly and caring when she's in a good mood. She is strongly hinted to be in love with Mamoru. Yuuka is strong willed and mature, and despite her temper sometimes, she is still willing to help her teammates.
4 years ago, Yuuka, along with Nagisa and Orine, were brought by Chieri to an abandoned mine where an AKB0048 concert was hold. After witnessing the concert and a battle between AKB0048 and the DES soldiers, in which AKB0048 won the battle, the four girls vowed to join one day AKB0048.
Yuuka's home life remains unmentioned, so it is not known if she ran away from home or went to the auditions with permission. However, it is revealed later during their return to Lancastar that her parents are revealed to be AKB0048 supporters. She receives an AKB0048 hologram card from an unknown source informing the viewer about the upcoming auditions and how to apply. She takes Orine and Nagisa to a quiet place and plays the hologram video to them. The three of them declare that they will audition to join AKB0048 and film their audition tapes in the hills.
Later, whilst walking home with Orine and Nagisa, Yuuka spots her boyfriend, Mamoru, walking just ahead of them. She runs up to him and they begin to chat. Later that evening, as Nagisa is taking a walk to clear her thoughts, she spots Yuka and Mamoru arguing in the park. Yuuka slaps him before he tells her that he loves her, embarrassing her. He says that he won't be able to love her if she becomes an idol. A furious Yuka says she won't give him an autograph when she becomes an idol and storms away.
The next day, on the road, Yuuka tells Nagisa and Orine she has received an answer from AKB0048 in which it said that all three have passed the auditions. Orine and Yuuka are happy about the news. Nagisa, however, seems sad. She tells them that she won't join them because of her father, which causes Yuuka to yell at her for being such a scaredy cat. Yuuka and Orine find Nagisa "asleep" outside near a mining operation. Yuuka covers her with her overcoat so Nagisa won't catch a cold.
The next day, Orine and Yuuka board an airplane and while the airplane begins its flight, they see Nagisa who follows the airplane, which indicates that she decided to join them after all. Orine and Yuuka manage to bring Nagisa on-board right before the airplane leaves Lancastar.
Later, in the selection round of auditions, she is seen carrying an unconscious Sonata on her back and shouting over to Orine (presumably asking her for bandages, as she is holding some and wrapping them around Makoto's leg). After the battle, which was revealed to be a simulation on an Entertainment Protection Sphere (or at least, non Entertainment Ban planet), she is accepted as one of the 77th Generation trainees of AKB0048.
Before the Lancastar understudy concert, she sends messages to both Mamoru and her parents. The former replies with a somewhat harsh-sounding warning not to come back. Initially, this makes Yuuka sad, but when she discovers that he is, in fact, a WOTA member, she is relieved and even mildly joyous over the fact that he researched AKB after she left and became a fan. When Nagisa declares her desire to rescue her father, Yuuka is one of the first to support her and decides to work with the WOTA members to distract the DGTO guards.
In the last episode, Yuuka falls off her flying stand when an explosion causes her to lose balance. She falls and Mamoru catches her and they share a moment of happiness and rejoicing. Their love reaches a climax here; however, she is unable to embrace or kiss him and resolves to just hold his hand while continuing to sing in a shaky voice as a promise to him. She then soon flies off to rejoin the other members.