Despite being born in Tokyo, Okamoto was actually raised in Hirakata, Osaka, where she also spent her elementary-school years.
[citation needed] In 1961, she made her debut for performing arts activities in comedy.
In 1970, she moved back to Tokyo, with subsequent transfer to the headquarters of the city, where she changed her name from "Noda Mutsumi" to her current name.
[citation needed] In 1971, she starred in the comedy film Tora-san's Love Call, as an extra.
[citation needed] In 1970, she had made her voice-acting debut in the anime series Inakappe Taishō, where she voiced Kikuko Ogaki.