Born Oyamada Keigo, Cornelius first started in the music industry in 1989 in with the influential Shibuya-kei band Lollypop Sonic, later to be renamed Flipper's Guitar, along with Owaza Kenji. However Flipper's Guitar's history was short, and it had only been two years before the duo split up in November 1991 and went out onto their own paths in their music careers. Following a one-year hiatus during which he established his own label, Trattoria, and produced other artists like Pizzicato Five and Kahimi Karie, Oyamada reemerged in 1993 as a solo artist under the moniker Cornelius, a tribute to the ape scientist from the sci-fi movie "Planet of the Apes"; the first release was the mini-album Holidays in the Sun, which was well-received by the critics. Likewise, his first two album releases - The First Question Award in 1994 and 69/96 in 1995 - sold well and were complemented with nationwide tours.
Between 1993 and 1996, Cornelius's music was well-liked by fans and critics and his popularity in Japan increased as he appeared in a number of commercials; he even hosted a radio show in 1995 and directed the music for the TV drama "Uwasano Tantei QAZ" in 1996. Cornelius's critical breakthrough came in 1997 with his third full-length album, Fantasma. For the album, Cornelius "cut and pasted" the history of pop and the 80's Britpop sound that his old band Flipper's Guitar was known for to create a rich and breathtaking musical collage. It became one of the most significant albums in Japan, and paved a way for an international following: in the advent of Fantasma's success, Cornelius signed on with the prestigious indie label Matador Records in 1998, and released the album in twenty-one countries and held three tours in Europe and the United States in June, September, and November of that same year. In the same year, he released two remix albums FM and CM, in which he collaborated with other musicians like the British bands Blur and UNKLE.
In 1999, Cornelius's popularity continued to grow as he performed at various events in Japan and toured extensively overseas. April and June saw his second festival tour in Europe, where he performed at the Glastonbury, Bowlie Weekender, and Roskilde music festivals. In August, he toured with rock favorite The Flaming Lips in the United States, followed by another tour in Europe. Cornelius returned to the United States again in October for the Coachella Music Festival. While he did not release any studio albums until 2001, Cornelius worked on a number of projects, such as producing Minekawa Takako (whom he would marry in 2000) and collaborating with Beck, Sting, K.D. Lang and other artists.
When his third full-length album Point was released in 2001 in Japan, fans and critics witnessed a significant change in style from Cornelius. Though Fantasma and Point shared the same musical influences, the former offered an organic, matured, and atmospheric soundscape. The new album did not have as much of an impact as its predecessor, but sold respectably nonetheless and was well received by music critics around the world upon its international release in 2002.
From 2002 to 2005, Cornelius continued to work with a number of different artists and toured internationally. In June 2002, Cornelius headlined the White Stage at the Fuji Rock Festival in Japan and February 2003 saw his first Australian tour. His song Drop (Do It Again version) was awarded Best Audience Show at the prominent North American digital film festival, RESFest. In addition to producing and joining forces with other musicians and remixing his own works, he also recorded and produced music for various companies, like Shiseido and Honda, and television programs.
In 2006, Cornelius released Sensuous, a crisp and carefully layered production that picked up and continued to explore the territories of atmospheric soundscapes first touched upon in Point. By then, Cornelius was no longer signed to Matador; for Sensuous's 2007 release in the United States, Everloving Records handled its distribution.
To the present, Cornelius is as busy as ever, despite saying that he would like to treat his highly successful career as a 9-to-5 office job. In addition to remixing and creating his own tracks and touring the world with cult-favorite indie bands like Deerhoof, he continues to work on producing artists and music for commercial use. It might be some time before fans and critics see another studio album from him, but it will be sure to please.
