Mamoru Oshii's first paid work was on Tatsunoko's Ippatsu Kanta-kun, but he gained prominence as director and storyboarder of the Urusei Yatsura TV series. He worked with Studio Pierrot for a while longer before leaving to work independently.
In 1996 Oshii created an anime film based on Masamune Shirow's manga Ghost in the Shell, which he followed up with a sequel film Ghost in the Shell 2: Innocence in 2004 and Ghost in the Shell 2.0 in 2008.
Oshii's "lifework," however, is titled the Kerberos saga. It spans all media, and has run for over 20 years-- it began with a radio drama in 1987.
In 2008 Oshii released a new film called the Sky Crawlers.