Honoka Yukishiro is a student at Verone Academy, progressing from her second to third year and sharing a class with Nagisa Misumi. She has round midnight blue eyes and long black hair with indigo highlights, partially pulled back by a cream clip featuring a magenta heart that secures her bangs to the right. Two strands of hair frame the area beneath her ears, extending to her shoulders. Her typical casual wear includes a pale blue top, a long white skirt, and a pale pink jacket with rolled-up sleeves, complemented by mauve translucent socks and white sandals decorated with a yellow star. She often carries a small sky blue purse with a blue pendant on her left side. During science club activities, she wears a lab coat and glasses. As an adult, her style remains similar, though she is taller with longer hair.

Her alter ego is Cure White, one of the two main Cures alongside Cure Black. When transformed, her hair lengthens and becomes curly, styled with a small top ponytail tied with a white ribbon adorned by a blue heart. She wears silver heart-shaped earrings and a short white dress featuring ruffled pale blue trim on the sleeves and a tulle petticoat tutu skirt with light blue scalloped lining and a blue horizontal line across the top. A white ribbon accents her chest, and a blue strap wrapped around her waist is fastened with a light blue heart that holds her Commune. The outfit includes white boots with pale blue soles, and leg warmers and gloves trimmed with sky blue ruffles, each bearing a light blue heart. Later appearances update her costume with a blue heart-shaped gem on her chest ribbon, a gold heart-shaped clasp on her belt, and added details on her leg warmers and gloves. Special forms like Super Cure White and Rainbow Cure White introduce further alterations, such as feather-like elements, gold accents, and golden wings.

Honoka is gentle and understanding, often prioritizing the well-being of others. She is highly intelligent, earning her the nicknames "The Queen of Knowledge," "The Queen of Intelligence," and "The Queen of Wisdom" among her peers, and she regularly uses her intellect to assist those around her. This quality contributes to her popularity, especially with male students, though she generally shows little romantic interest. She is serious in her pursuits and can become strict, forceful, or intimidating when faced with laziness or apathy, driven by a desire for others to excel. A stubborn and occasionally pushy side emerges in her efforts to help, though she usually maintains an easy-going and calm demeanor, particularly in contrast to Nagisa.

Her relationships form a key part of her life. She develops a close friendship with Nagisa Misumi, starting with little in common but growing closer over time until they use given names for each other. She cares deeply for Nagisa's younger brother, Ryouta, who sees her as an elder sister figure. She is protective and considerate toward Kujou Hikari. Her interactions with Kiriya are significant, as she helps him understand human emotions and views him as a little brother; his betrayal and subsequent death cause her profound distress. She maintains a long-standing platonic friendship with her childhood friend Fujimura Shougo and supports Nagisa's romantic interest in him. Her grandmother, Yukishiro Sanae, provides wisdom and advice, and Honoka holds great affection for her, preferring to keep her Pretty Cure identity a secret from her.

Alongside Nagisa, Honoka becomes a Pretty Cure to fight the Dotsuku Zone and collect Prism Stones for the Garden of Light. As Cure White, she specializes in agility and intelligence-based combat, contrasting Cure Black's physical strength. In a spin-off narrative, an alternate adult version of Honoka travels with Nagisa to the Dark Zone, where she is captured and turned to stone. Freed and brainwashed by the Dark King, she becomes Witch, an antagonist with control over thunder and the ability to enhance enemies using a white Sky Jewel Key. As Witch, she wears a long purple dress with a dark blue belt and a purple witch-like hat, with long dark blue hair. After purification, she regains her ability to transform into Cure White, employing attacks like White Thunder and Yang Thunder with specific keys and weapons. She also joins combined attacks with other Cures, such as the Extreme Heart Sky Jewel.

The etymology of her name reflects elements of her character. "Yukishiro" can be interpreted as "snow castle," with "snow" relating to her Cure White identity and "castle" alluding to her family's wealth and large home. "Honoka," written in hiragana, lacks a definitive kanji meaning, but common interpretations include "spike flower" or "spike fragrance," suggesting a connection to nature and elegance.