NEEKO is the stage name of Isuzu Nishihagi, a Japanese voice actress, singer, and model born on October 28, 1983, in Hyogo Prefecture. Her career in entertainment began in 2001 as a reader model for fashion magazines. She also gained experience as a singer for the independent band SLIP for three years starting in 2003.

NEEKO's voice acting debut came in 2006 with her casting as the infant hitman Reborn in the long-running anime series Kateikyoushi Hitman Reborn!. This role became her most iconic and is considered her breakout performance. She voiced the character for the entire television series, reprised the role in multiple original video animation projects, and featured in numerous video game adaptations based on the franchise. A specific example of her work in this series is the special episode Reborn!: Here Comes a Vongola Family-Style School Trip!. For the Reborn! series, she also demonstrated her creative abilities by writing lyrics and composing music for several character songs.

Beyond her work in the Reborn! franchise, NEEKO has taken on a variety of other roles. In 2019, she voiced the character The 3 Witches in the anime film Dayan to Tama to Tobi Neko to: Mittsu no Neko no Monogatari. Other notable anime roles include Chikurun in Mahoutsukai PreCure! and Warechu in the game and anime adaptations of the Hyperdimension Neptunia series. She also contributed to series such as Aikatsu Friends!, Digimon Universe Appli Monsters, and the short-form anime series Aim for the Top! ~Animal Academy~.

Throughout her career, NEEKO has balanced voice acting with her other artistic pursuits. She released her first solo album, Seishun Shampoo, in May 2010. Her involvement with music also included forming a band called Seishun Shampoo in 2008. She has maintained a connection to the fashion world, serving as a model and endorser for clothing brands. NEEKO is affiliated with the talent agency Smile Maker.