Közi's career began at the end of the 1980s in Beyond The Reinsight. Information about this band is very scarce. In 1991 he joined 摩天楼(Matenrou) with future MALICE MIZER member Mana and released two demo tapes. Mana and Közi left Matenrou after deciding they both had similar ideas about creating music. They formed Malice Mizer in 1992. After Malice Mizer disbanded in 2001, Közi joined Haruhiko Ash and created Eve of Destiny, an industrial rock band that toured outside of Japan, performing at various festivals in Europe.

In 2002, Közi collaborated with Japanese author Minako for the book Izayoi No Tsuki (十六夜の月), which Közi provided the eerie soundtrack for. He then performed a special singing event in Japan which cemented the fact that he was following a solo career. Közi's first solo release was the double-disc, double-single package KHAOS/KINEMA, which included "Promenade". The track was re-released several months later on his debut album Catharsis (カタルシス). Közi's MEMENTO single is dedicated to the late Malice Mizer drummer, Kami.

During his time in Malice Mizer, Közi often assumed the role of a pierrot doll, dressing in clown-like costumes with large ruffs, always in shades of red, his favourite colour. In music videos and on-stage he would often make movements reminiscent of a marionette (string puppet). Közi has continued this visual style to some extent, but his contemporary stage costumes are more gothic. His work on the Izayoi No Tsuki project was reminiscent of carnival music, and artwork for his projects usually follow a dramatic, theatrical theme. Details about his private life are sketchy.

On May 2007, Közi released a live DVD, featuring a collage of his lives from 2004-2006.

In 2008, Közi embarked on a project with ex-Deadman's vocalist Mako. He'll be the bassist and guitarist for the single track CD that will be included with Mako's book "buried alive by words." The song will be called "buried with the light," and will be released in May.