Yamashita was born on July 26, 1999 in Tokyo. Her entertainment career began in 2016 when she successfully auditioned for the third generation of the idol group Nogizaka46. Yamashita and her fellow third generation members performed their first full live concert in May 2017.

Yamashita’s first selection for Nogizaka46’s main performance group came in March 2018, when she was selected for Nogizaka46’s twentieth single “Synchronicity”. She has since been selected for the main performance groups for the group’s twenty-first single “Jikochu de Ikō!” and twenty-second single “Kaerimichi wa Tōmawari Shitaku Naru”. She has also been selected to appear in advertising campaigns for Mouse Computer, 7-Eleven, Fanta, and Pokémon Go.

Yamashita became an exclusive model for the fashion magazine CanCam in August 2018. Two months later she made her acting debut with a minor role in the film Every Day a Good Day, an adaptation of Noriko Morishita’s essay about finding happiness through the Japanese tea ceremony. Two stage roles followed, with Yamashita appearing in a stage adaptation of Sailor Moon alongside fellow Nogizaka46 members, and in the horror play Zambi alongside several members of Nogizaka46 and Keyakizaka46.

In 2019, after reprising her Zambi stage role for the Nippon TV adaptation of the play, Yamashita played the supporting role of nurse Mami Ichinose in the 2019 BS TV Tokyo ensemble drama Cheers to Miki Clinic (神酒クリニックで乾杯を, Miki Kurinikku de Kanpai wo), an adaptation of the novel of the same name by mystery writer Mikito Chinen. Her first lead role came in the TV Tokyo series Video Girl Mai (電影少女 -VIDEO GIRL MAI 2019-, Denei Shōjo: Video Girl Mai 2019). The series continued TV Tokyo’s previous live-action adaptation of the manga Video Girl Ai, which starred Nanase Nishino as Ai, but focused on a new main character, Mai Kamio, played by Yamashita. Later that year she joined the cast of the live-action film adaptation of the manga Eizouken ni wa Te o Dasu na! alongside fellow Nogizaka46 members Asuka Saitō and Minami Umezawa.

Yamashita’s first photobook, titled Wasurerarenai Hito (lit. Unforgettable Person), was published by Shogakukan in January 2020. The photobook sold over 100,000 copies in the first week after publication, and ranked first in weekly sales in the Oricon photobook and general book categories.