Kotono Mitsuishi is a highly influential Japanese voice actress and narrator, born on December 8, 1967, in Toda, Saitama Prefecture. After graduating from high school in 1986, she entered the Katsuta Voice Actor's Academy, where her classmates included notable voice actors Toshiyuki Morikawa and Wataru Takagi. She made her voice acting debut in 1988, voicing Tomoyo in the OVA Ace wo Nerae! 2.

Mitsuishi became a household name with her first major role as Usagi Tsukino, the title character in the iconic magical girl anime Sailor Moon, which began airing in 1992. This performance launched her career and established her as a leading voice actress during the idol seiyuu boom of the early 1990s. She is renowned for her loud and energetic vocal style, as well as her ability to deliver rapid-fire dialogue. Her popularity was further solidified by her role as the complex and beloved Misato Katsuragi in the landmark series Neon Genesis Evangelion.

Throughout her extensive career, Mitsuishi has taken on a wide array of iconic characters. She has portrayed strong female leads such as Murrue Ramius in Mobile Suit Gundam SEED and Mobile Suit Gundam SEED Destiny, the pirate empress Boa Hancock in One Piece, and Excel in the hyperactive comedy Excel Saga. She also voiced Mireille Bouquet in the assassin thriller Noir and Juri Arisugawa in Revolutionary Girl Utena. Her versatility extends to playing Urumi Kanzaki in Great Teacher Onizuka, Kagura Soma in the 2001 Fruits Basket, and Jean in Claymore.

In more recent years, Mitsuishi has continued to be a prominent presence in the industry, often revisiting or continuing her legacy roles. She has reprised her part as Usagi Tsukino in the Sailor Moon Crystal series and its subsequent films, Pretty Guardian Sailor Moon Eternal and Pretty Guardian Sailor Moon Cosmos. She returned to the role of Misato Katsuragi in the final Rebuild of Evangelion film, Evangelion: 3.0+1.0: Thrice Upon a Time. She has also taken on new, popular characters, including Mei Mei in Jujutsu Kaisen, Tae Yamada in Zombie Land Saga, and Sati Saigan in the 2021 Shaman King adaptation. Another significant ongoing role is that of Tamako Nobi, Nobita's mother, in the Doraemon franchise since 2005.

Beyond anime, Mitsuishi works extensively as a narrator for series such as Date A Live and has appeared in live-action television dramas like Get Ready! and the taiga drama Dear Radiance. Over her career, she has frequently collaborated with a wide range of fellow voice actors. Data from behind-the-scenes credits indicates she has worked with Takehito Koyasu on numerous projects more than any other actor, followed by frequent collaborations with Tomokazu Seki and Akira Ishida.

Mitsuishi was previously affiliated with Arts Vision and is now freelance. In recognition of her distinguished career and her role in broadening the profession of voice acting, she was awarded the Kazue Takahashi Award at the 8th Annual Seiyū Awards in 2014.