Born in Chicago in 1969, O’Rourke graduated from DePaul University with a degree in composition. He first came to prominence in his early twenties as a member of Illusion Of Safety and of prescient avant-folk group Gastr Del Sol with David Grubbs. As a producer he was in demand within the avant-garde of an older generation: Faust, Tony Conrad, The Red Crayola. Beginning in 1999 he played bass guitar, guitar, and synthesizer with Sonic Youth, in addition to holding recording and mixing duties with the group.

He's collaborated with such contemporary improv greats as Derek Bailey, Henry Kaiser, Eddie Prevost, and Keith Rowe (of English improv group AMM), KK Null, David Jackman (Organum), and early krautrock experimentalists Faust; he has been commissioned to compose works for the Kronos Quartet and the ROVA Saxophone Quartet; and he played for the Merce Cunningham Dance Company for four years, together with music director Takehisa Kosugi. But it was his 1999 album, Eureka (Drag City), that introduced him to a broader audience, through its accessible melodies and pop tones and textures reminiscent of Burt Bacharach.

After several years in New York, O’Rourke relocated to Japan in 2006 and now maintains a regular presence on the local Tokyo live circuit. He plays with avant-garde icons such as Keiji Haino and Merzbow, joins visiting jazz musicians, and performs in his regular band with keyboardist Eiko Ishibashi, bassist Toshiaki Sudoh, and drummer Tatsuhisa Yamamoto.

The Editions Mego sublabel, Old News, is a vinyl-only imprint on which O’Rourke releases unknown works from across the breadth of his archive, as well as newer recordings. In 2013, O’Rourke released eight albums-worth of rare material collectively called Steamroom 1-8.