As an actress her lead roles have included Mana Hayase in the Japanese remake of You Are the Apple of My Eye, and Midori Asakusa in both the film and TV adaptations of Keep Your Hands Off Eizouken!.

[9] In 2015, Saitō became the exclusive model for the fashion magazine CUTiE published by Takarajimasha, which stopped publication in the same year.

[20][21] She has played lead roles in the Japanese remake of the Taiwanese film You Are the Apple of My Eye and the NTV horror drama Zambi.

[24] On January 9, 2023, it was revealed that Saitō was cast for both the film and television drama live-action adaptation of the manga My Home Hero as Reika Tosu, an 18-year-old college student trapped in an abusive relationship at the start of the story and who later becomes a police investigator after a timeskip.

[25] In January 23, 2024, it was announced that she is also set to star as Ai Hoshino for the live-action film adaptation of the manga Oshi no Ko.