She began her singing career in 2000, debuting as a member of the trance group I've Sound and releasing her first mini-album Sora o Tobetara that same year.

She has contributed songs to numerous anime and video games including Please Teacher!, Maria-sama ga Miteru, Hourglass of Summer, Hayate the Combat Butler, Kannazuki no Miko,[2] Shakugan no Shana, BlazBlue: Calamity Trigger, To Love-Ru,[3] Accel World, Phantasy Star Online and Argevollen, among others.

[4] Her first successful audition was with I've Sound, a team of producers using the talents of various female vocalists for their productions — best recognized for their many dating sim and eroge game soundtracks.

Her first official performance in North America was her highly successful American concert debut at Anime Expo 2005,[8] soon followed by the Kotoko Lax Tour.

Her 17th single "Light My Fire" was written by Ryo of Supercell and was used as the first opening theme to the 2011 anime series Shakugan no Shana Final.