Akari Sakura is the main human protagonist of Jewelpet Twinkle. She is a young student from Hayama in Kanagawa Prefecture, attending the Winston Educational Institute. Initially eleven years old, she turns twelve as the series progresses. Akari is the younger sister of Monica Sakura, a famous teen idol and student council president, and she lives with her parents: her father, Akira, is a shipbuilding architect, and her mother, Marie, works as a chief editor for a magazine.

Akari is characterized as a bright, gentle, and deeply shy girl who is often easily embarrassed. Due to her older sister's overwhelming popularity and success, she has developed a significant inferiority complex and feelings of jealousy. This has made her withdrawn and hesitant to express herself, as she constantly feels overshadowed and compared to Monica. Despite this, her core personality is one of understanding and compassion. She is an All-Loving Hero type who is always concerned about others, never bad-mouths people, and is quick to offer help and encouragement. Her primary dreams and motivations are to become a famous manga artist and to be with the boy she likes, Yuuma Jinnai. She decides to enter the Magic Academy in Jewel Land with the goal of winning the Jewel Star Grand Prix, hoping to make her wishes come true and find a way to distinguish herself.

Akari's story begins when she accidentally meets Ruby, a white rabbit Jewelpet, on a beach. Initially hesitant and wanting nothing to do with the magical creature, she has a change of heart after a heartfelt conversation, at which point a Jewel Charm materializes in her hand, marking the beginning of her magical journey. She enrolls in the Magic Academy, becoming Ruby's human partner, and later also partners with Labra. Her role is that of a late-blooming but exceptionally talented student who must learn to control her powers and overcome her self-doubt. Her key relationships include her deep, albeit initially unspoken, love for her classmate Yuuma. She is also rivals and friends with fellow students Miria and Sara. A significant portion of her development involves reconciling with her sister Monica, understanding that her mother cares for both of them equally, and gradually building her self-confidence to step out from her sister's shadow.

Throughout the series, Akari undergoes considerable development. She starts as a timid girl who can barely say good morning to her crush, but she grows into a more assured and cheerful individual. Her family notes that she has become noticeably happier since Ruby came into her life. She gains the courage to confess her feelings to Yuuma and becomes more proactive in her friendships and magical training. In the climax of the story, she plays a crucial role in saving Alma from the influence of the Battest, even allowing herself to be possessed to reach the character's heart. This act leads to her becoming the winner of the Jewel Star Grand Prix and the current holder of the Jewel Star title.

Regarding her magical abilities, Akari is initially shown to be clumsy and not as skilled as other students. However, she possesses immense latent magical potential, which is often unlocked when she has something or someone she is determined to protect. She performs magic by using her Jewel Charm in conjunction with her Jewelpet partners, Ruby and Labra. When casting spells, she typically transforms into a pink magical costume that amplifies her power. Her magical potential is considered the greatest of all the students, culminating in her becoming the most powerful wizard by the end of the series. In a notable moment, she is briefly possessed by the Battest, which transforms her costume into a black version with dark wings.