Nagisa Saitō is a Japanese entertainer who began her career as an idol before transitioning to acting and, more recently, to voice acting in anime. She first gained public recognition as a core member of the idol group =LOVE, a group produced by Rino Sashihara. Saitō was frequently positioned as the center of the group during her tenure. She remained with =LOVE until January 2023, when she graduated from the group to pursue a full-time career as an actor.

Following her departure from the group, Saitō focused on live-action roles in film and television. She gained significant attention for her performance as Yua Takahashi in the drama series Tomorrow, I'll Be Someone's Girlfriend in 2022. Her subsequent work includes a role in the live-action film adaptation of the popular manga and anime Oshi no Ko. In this 2024 film, she portrayed the character Mem-cho. She has also appeared in other films such as The Anonymous Love Exchange Diary and My Dear Monster.

Saitō made her debut as a voice actor in anime in 2025. Her first role was in the second season of the Pretty Series, titled Himitsu no AiPri: Ring-hen, where she voiced the character Wako Sensei, the librarian at Paradise Academy. Saitō had previously served as an ambassador for the franchise. This marked her first attempt at anime voice acting, a transition from her established career in live-action television and film.

In addition to her performing career, Saitō has worked as a regular model for the fashion magazine LARME. She was born on July 6, 2003.