Rina Yamaguchi is a Japanese performer affiliated with the talent agency LDH. She was born on November 22, 2008, in Kanagawa Prefecture. Her early training began around 2015 at EXPG Yokohama, a dance and vocal school associated with LDH, where she received instruction in singing and dance. In 2018, she participated in LDH's The Girls Audition, which served as a catalyst for her subsequent roles in the Girls x Heroine television series.

Yamaguchi's acting career commenced in 2019 when she was cast as the antagonist Sarai in the television series Secret x Heroine Phantomirage. She reprised a version of this character, Sarai Shihara, as a main cast member in the subsequent series Police x Heroine Lovepatrina, which aired from 2020 to 2021. As part of the Lovepatrina cast, she became a member of the temporary idol unit Lovely2, which was formed within the context of the show. During this period, her activities included modeling for brands and appearing in music videos for the related group Girls2.

Following the conclusion of Lovely2's activities, it was announced in June 2021 that Yamaguchi would debut as a member of a new girl group, Lucky2. The group provided theme songs for the fifth season of the Girls x Heroine franchise, Bittomo x Heroine Kirameki Powers. In 2022, Yamaguchi and her Lucky2 colleagues became regulars on the children's variety program Oha Suta, serving as Oha Girls.

Yamaguchi's foray into anime voice acting came with her role in the series GaruGaku. II: Lucky Stars. This anime, which aired in early 2022, was a sequel that starred the members of Lucky2 as the main cast. In this series, Yamaguchi provided the voice for a fictionalized character also named Rina, a girl from Kanagawa Prefecture who is new to singing and dancing and is a fan of the group Girls2. The story follows her and her fellow group members as they aspire to enter a prestigious performance academy.