Sasahara learned to play the piano at a young age and dreamed of becoming a singer during her elementary school years. She was persuaded against pursuing that career by her parents, who advised her that becoming one was difficult.[2] While in junior high school, she played the clarinet as a member of her school's brass band. Around this time, she was encouraged to pursue a career in voice acting by her father, who told her that she could sing, act, and appear on TV in that line of work.[2][3] Her father then encouraged her by printing out an audition form for a role in the Japanese dub of the film The Golden Compass, although she ultimately did not push through with auditioning.[2][3] Nevertheless, as she had already been interested in anime and manga, the experience influenced her to investigate voice acting more and learn about anime production.[2]
During her third year of high school, Sasahara applied for enrollment at the Japan Narration Acting Institute.[3] After passing the entrance examinations, she enrolled at the school while also going to university.[2][3] While in her third year of training, she received a notification that the she had been accepted into the I'm Enterprise talent agency;[2] she then debuted as a voice actress in 2016.[2] Among her earliest roles was as the character Li Xuelan in the 2018 anime series Märchen Mädchen.[3][4] Later that year, she was cast in her first main role as the character Akari Amano in the anime series Ms. Vampire Who Lives in My Neighborhood.[2][5] The following year, she was cast as Rū Hitoma in the anime series Over Drive Girl 1/6 and Rin Namiki in the multimedia franchise Kandagawa Jet Girls.[2][6] In 2020, she was cast as Yūki Kuroiwa in the anime series Diary of Our Days at the Breakwater.[7] In 2021, she was cast as Emilico in the anime series Shadows House.[8]
