Haruko Momoi is a Japanese voice actress, singer, and songwriter born in Tokyo on December 14, 1977. She began her entertainment career by singing and performing on the streets of Akihabara and Harajuku in the late 1990s before making her formal debut as a singer in 2000 with the single Mail Me. Her career as a voice actor commenced in 2001 with her role as Komugi Nakahara in the television anime The Soul Taker. Soon after, she formed the musical duo UNDER17 with composer Masaya Koike, a group that performed theme songs for various anime and games before disbanding in 2004.

Momoi is recognized for a distinctive vocal quality, often using a high-pitched or nasal tone that has become her trademark. Among her early and recurring anime roles is Utamaru, a small, animal-like mascot character in the Da Capo series, including D.C. ~Da Capo~ and D.C.III ~Da Capo III~, an example of her ability to voice non-human characters. Another notable early role is Chika Minazuki in Ai Yori Aoshi. She has also voiced San Seto, the energetic younger sister of the main heroine in My Bride is a Mermaid. In the realm of video games, she is well known as the voice of Anise Tatlin in the popular role-playing game Tales of the Abyss, a role she has reprised in multiple spin-off titles. She also voices the character Faris NyanNyan (also known as Rumiho Akiha) in the acclaimed science fiction visual novel and anime series Steins;Gate and its sequel, Steins;Gate 0. Other notable video game roles include Mayaa in Ragnarok The Animation and various characters in the long-running Phantasy Star Online 2.

Throughout her career, Momoi has demonstrated strong ties to the Akihabara district of Tokyo, openly identifying as an otaku and earning a reputation as an "Akihabara electric wave" personality. She has frequently collaborated with fellow voice actresses Masumi Asano and Sakura Nogawa, who often appear alongside her in the same productions. In 2007, she published an autobiography titled Akihaba-LOVE, which details her life and career experiences. A significant achievement in her career was the founding of her own record label, AKIHABA LOVE RECORDS, in 2009. Beyond her work in Japan, Momoi has been a guest at international anime conventions, including appearances in Germany and Australia.