Hailing from Kanagawa, Shin Ichijō transitioned from soccer to Prism Shows after a fateful Tanabata Day encounter with Louis Kisaragi. Louis gifted him a pendant and a ticket to an Over The Rainbow performance, igniting Shin's dream to emulate Hiro Hayami. He enrolled at Edel Rose Academy under Himuro Hijiri's guidance.

As the academy's newest member, Shin displayed innate talent despite his novice status. His cheerful, optimistic, and genuinely kind personality made him approachable, though his innocence sometimes led to unfiltered emotional expressions. During early training, he met Kouji Mihama at an underground rink. Their Prism Battle revealed Shin's unique "Prism Rush" technique, capable of evoking the primal joy of Prism Shows. Kouji gifted him the pivotal song "Over The Sunshine."

At the Rose Party, following Over The Rainbow's hiatus announcement, Shin performed "Over The Sunshine" at Hijiri's urging. Channeling Kouji's message to "make everyone smile again," his debut successfully revitalized the audience, showcasing his evolution from admirer to performer. Subsequent revelations uncovered Shin's ancient link to Shine, a destructive entity sealed within him a millennium prior by Louis—revealed as the ancient figure Rinne. Shine serves as the source of Shin's Prism Sparkle, making Prism Jumps impossible without its power. Louis chose to preserve Shine to ensure Shin could continue performing.

Shin possesses short dark blue hair, red eyes, and a dark crescent moon marking on his neck symbolizing Shine's presence. He consistently wears Louis's pendant. His story intertwines with the Tanabata legend, reflecting Louis's statement about crossing "a thousand years just to meet him." Born on February 29th, 2001—a non-leap year devoid of that date—Shin dislikes celery unless prepared by a specific individual. His songs include "Over The Sunshine!," "Dramatic LOVE," "Sweet Sweet Sweet," and "Happy Happy Birthday!"