Machiko Toyoshima is a Japanese actress, voice actress, and singer born on December 28, 1971, in Ibaraki Prefecture, Japan. She is affiliated with the talent management firm Aoni Production. Inspired by anime such as Mobile Suit Gundam and the works of Hayao Miyazaki, Toyoshima pursued a career in voice acting. She graduated from Meiji University and is a graduate of the Aoni Juku training school, Tokyo branch's 14th term.

Toyoshima began her professional voice acting career in 1994, taking on various roles in children's and family-oriented anime series such as Kirin no Yume and the long-running franchise Soreike! Anpanman. Early in her career, in 1997, she formed a short-lived musical unit called GIRLS BE with fellow voice actress and friend Houko Kuwashima, for which they released music tied to the manga BOYS BE….

Her filmography is extensive and includes a wide range of characters across anime, video games, and OVAs. In television animation, her notable roles include Kuina in One Piece, PallaPalla in Sailor Moon SuperS, Fujii in Slam Dunk, Noriko Nakajima in Jigoku Sensei Nube, and Misha in the Growlanser video game series. She also voiced multiple characters across different eras of the Gegege no Kitarō franchise, including Child-Nurikabe, Kuro, and Rokuro-Kubi. In the Pokémon anime, she provided the voice for Misty's Horsea. She has also appeared in series such as Hunter x Hunter, World Trigger, and Cyborg 009.

A significant achievement in her career came in 2016 when she was selected to succeed the late Yuko Mizutani as the voice of Sakiko Sakura, the elder sister in the nationally beloved anime Chibi Maruko-chan. This role brought her widespread recognition as a "national elder sister" and connected her to a new generation of viewers. In the same series, she also took over several other minor roles previously voiced by Mizutani.

Beyond anime, Toyoshima has been active in original video animations and video games. Her OVA credits include the title role of Amy in Kirara and Kawana Misaki in ONE ~Kagayaku Kisetsu e~. In video games, she is known for roles such as Lulula Franc in Money Puzzle Exchanger, Manami Sugihara in the Sentimental Graffiti series, and Koharu Fujishiro in Kaitōranma. She has also worked extensively as a narrator for television programs and commercials, and has performed in stage productions and reading dramas. In addition to voice work, she holds certifications in English and Kanji, and has interests including soccer, cooking, and yoga.