Miyako Kamijō is the older sister of Hikari Kamijō and serves as a pivotal figure in her life. She embodies the qualities of a time-tested maturity, offering wisdom in serious decisions and unwavering support. Miyako readily includes Hikari in her own concerns and ideas while intuitively understanding her sister's worries and aspirations. She is quick to offer compliments and encouragement, particularly during Hikari's performances.

Miyako is often present in the audience at Hikari's competitions or at home preparing dinner alongside Hikari and their mother. By the series' conclusion, she is revealed to be in a relationship with a boyfriend named Arnaud. Miyako is regarded as a Cool Big Sis figure.