During her time in high school, she stayed in Pennsylvania, where she participated in a homestay program to learn English. She takes time off to practice English when she's not busy with voiceover work.
She voiced Puchiko in the English dubbed release of Leave it to Piyoko, making her the first and one of the few Japanese voice actors to have reprised a role in English in addition to the original Japanese performance.
In 2018, fellow voice actress Mayumi Tanaka announced that Sawashiro had successfully given birth to her first child.
She participated in voice actor auditions of Di Gi Charat on May 2, 1999, and she won the Special Jury Prize.