Miyuki Chinen leads the popular dance group Trinity and later coaches the main characters' group, Clover. She has long fuchsia hair, usually secured in a ponytail with a red accessory, complemented by striking yellow eyes and lipstick. Her performance outfit features a ruffled pale pink elbow-length top with white furry shoulders, layered over a black and red corset-like tank top, a light red mini-skirt with ruffled trim, and cherry-colored boots. For casual settings or practice, she opts for simpler attire: a red and white tank top over a lighter red long-sleeved shirt, baggy black pants, and red/white sneakers, with her hair styled less tightly and without lipstick or earrings.

Her personality balances inherent kindness with professional rigor. Despite her fame, she maintains a friendly demeanor and welcomes anyone genuinely interested into her dance classes. Yet she enforces strict discipline, addressing shortcomings directly when expectations aren't met. Miyuki consistently shows concern for others' well-being, particularly her students' health and dedication.

She shares a mentorship with Momozono Love, offering lessons after Love rescues her from a Nakewameke attack. While caring deeply, Miyuki upholds strict standards in training. She also shares a close, teasing relationship with her younger brother, Chinen Daisuke, occasionally referencing his romantic feelings for Love.

Miyuki's story begins with her rescue in the first episode, leading her to become Love's instructor. Her role remains minor until she discontinues the girls' lessons due to recurring tardiness. This coincides with Love discovering Daisuke is Miyuki's brother, prompting Miyuki to forgive the group and resume coaching. Later, the girls confide their dual Pretty Cure identities to her, mistakenly believing she might be the fourth member before Setsuna's role is revealed.

In an official novel adaptation, Miyuki is temporarily transformed into one of Maphisto's Fushiawase monsters before the Cures rescue her. She initially choreographs dances to "You make me happy!" before switching to "H@ppy Together!!!" for training. Miyuki is the first non-Cure character to learn the Cures' secret identities and provide ongoing support. Her design draws inspiration from Japanese singer Amuro Namie.

While her brother Daisuke is confirmed born in Okinawa, Miyuki's birthplace is unspecified. Her Okinawan-origin surname "Chinen" suggests a potential regional connection.