Hibiki Hōjō is a fourteen-year-old student in class 2A of the private Aria Academy. Coming from a deeply musical family, she is the daughter of a famous musician father and a world-renowned violinist mother. Despite this environment, Hibiki harbors a complicated relationship with music, having stopped playing the piano for a time after a childhood performance where she felt she had disappointed her father, leading her to believe she possessed no real musical talent even though she has perfect pitch.

In her daily life, Hibiki is an energetic, bright, and highly athletic girl who loves sports and hates to lose. Her sense of justice is strong, and she has a straightforward, impulsive, and sometimes clumsy nature. She is a major food enthusiast with a particular weakness for sweet things, and her favorite treats are the cakes from the Lucky Spoon bakery, which is run by the family of her friend Kanade. This fondness often leads her to sneak into the school's Sweets Club to steal pastries, which frequently causes arguments with Kanade. In contrast to her physical prowess, Hibiki struggles significantly with her studies and is not skilled at cooking or drawing. While she appears outgoing and confident, she is susceptible to loneliness, partly due to being an only child and often being alone at home because of her parents' busy careers. She envies friends who have siblings and eagerly embraces younger individuals like Ako into her circle.

Hibiki's role in the story is set in motion by her deep connection to sound, which makes her a target for the evil Minor Land. Alongside her childhood friend Kanade Minamino, she is chosen to become a Pretty Cure, transforming into the pink-haired warrior Cure Melody. Her transformation is aided by the pink Fairy Tone named Dory, and her introductory phrase as Cure Melody is, "Playing the wild tune, Cure Melody!". The initial premise requires that she and Kanade, who become Cure Rhythm, fight together, as they cannot transform or reach their full potential alone.

The most critical relationship in Hibiki's life is with Kanade Minamino. They are childhood friends who had a falling out and spent the time before the series bickering constantly, despite secretly wishing to reconcile. Their journey as Pretty Cure forces them to confront the misunderstandings that drove them apart, allowing them to rebuild a strong partnership based on mutual trust and care, though their friendly arguments continue. She also shares a close, sisterly bond with the fairy Hummy, who lives with her. Hibiki plays a key role in redeeming former enemies; her straightforward kindness and refusal to give up on them help both the villainous Siren, who later becomes the Cure Beat named Ellen Kurokawa, and the initially cold and mysterious Cure Muse, Ako Shirabe, to join the team.

Throughout the series, Hibiki experiences significant personal development. She must overcome her past trauma with music to find her own voice and passion for playing the piano again, eventually setting a goal to become a pianist. She grows from a girl who acts impulsively into a natural leader who can unite her teammates and help them find harmony. As Cure Melody, her abilities are music-based, utilizing a weapon called the Miracle Belltier, which uses the Fairy Tone Miry. Her solo attack is Precure Music Rondo, and she performs the joint attack Precure Passionate Harmony with Cure Rhythm. At a critical point, she is the first to hear the voice of the legendary Crescendo Tone, proving her unique potential as a leader. With the power of Crescendo Tone, she can achieve an advanced form known as Crescendo Cure Melody, which features golden, angel-like wings and significantly enhanced power.