Yoichi Hanasaki is Tsubomi Hanasaki's supportive father and Kaoruko Hanasaki's son. Married to Mizuki Hanasaki, he co-manages their family flower shop in Kibougahana. This career shift followed a pivotal moment when he and Mizuki witnessed Tsubomi's hidden distress after Mizuki returned home for a forgotten item, revealing the loneliness beneath their daughter's cheerful farewells during their demanding previous jobs. Prioritizing family stability, they chose the flower shop life for proximity to Tsubomi.

Before Kibougahana, Yoichi worked as a university researcher. A botanical garden visit for studies brought him face-to-face with Mizuki, who was seeking flowers for her Red Florian project. Their meeting sparked immediate mutual affection, leading swiftly to marriage and Tsubomi's birth. Initially, both maintained separate careers, frequently relying on Kaoruko for Tsubomi's care.

Yoichi fosters a gentle, trusting bond with Tsubomi, serving as her confidant and adviser. He demonstrated this commitment by declining a former student's job offer to reassure Tsubomi about their dedication to the shop and family. His encouraging nature shines when he uplifts a hesitant former student, Obata, comparing him to a resilient sunflower to restore his confidence.

He remains unaware of Tsubomi's secret life as a Pretty Cure or Kaoruko's history as Cure Flower. His focus centers on nurturing the family business and Tsubomi's well-being. His name, Yoichi (陽一), meaning "one sun," and Hanasaki (花咲), meaning "blooming flower," reflect his botanical connection and radiant presence.