Sayaka Ueshima is a first-year student at Myoudou Academy with a boyish appearance: slightly tanned skin, short choppy red hair, and matching red eyes. She wears a raspberry-colored uniform with black tube socks and shoes.

Her deep passion for soccer began in elementary school, where she played freely with boys and girls. In middle school, the soccer club rejected her repeated requests to join due to her gender, causing frustration. When Erika Kurumi invited her to the fashion club, Sayaka insulted it as dull, triggering her Heart Flower—a red poinsettia symbolizing "burning with passion"—to wilt visibly.

While practicing soccer alone under a bridge, her wilting Heart Flower drew Sasorina of the Desert Apostles, who fused it with Sayaka’s soccer ball to create a Desertrian. Semi-conscious during the transformation, Sayaka witnessed the chaos until Cure Marine purified the Desertrian with a Blue Forte Wave attack. Awakening afterward, she accepted Tsubomi Hanasaki and Erika’s explanation that she had overexerted herself and dreamed the events. The purification restored her Heart Flower and reignited her soccer passion.

Refusing defeat, Sayaka resolved to start an all-girls soccer club. She informed Erika of her recruitment plans. Days later, journalist Kanae Tada interviewed her about her "dream" encounter with the Pretty Cures for a news story.

Her efforts succeeded when the school officially recognized the girls’ soccer club. During practice for a tournament, Sasorina and her Snackeys challenged the team to a match. Dark Pretty Cure attacked and injured Sayaka, who was later found by Tsubomi and Erika. She recounted being defeated by a Pretty Cure, unaware of Dark Pretty Cure’s true nature.

In the series finale, Sayaka survived antagonist Dune’s transformation of Earth into a desert. She and other survivors supported the Pretty Cures’ mission from Earth, concluding her arc with unwavering dedication to soccer and her team.