Ollie studied electronic music in the mid-1970s under [a1027800], a German composer living in Australia who had studied under Karlheinz Stockhausen. In 1978, Ollie formed one of the first electronic bands, Whirlywirld, releasing a number of recordings on undefined. During the next ten years Ollie formed experimental outfits Hugo Klang, Orchestra of Skin and Bone, and the hard-core industrial techno band, [a274852].

Ollie produced the [url=https://www.discogs.com/master/38340-Various-Dogs-In-Space-Original-Motion-Picture-Soundtrack]soundtrack[/url] of "Dogs In Space" (1986), performed on several of the tracks and wrote "Rooms For The Memory" sung by Michael Hutchence. Ollie was subsequently approached by Michael Hutchence to produce an album with him and the result was Max Q. Ollie also worked at this time with American producer Todd Terry and UK producer/DJ Paul Oakenfold.

From the success of Max Q came a major record company deal and Ollie formed the band Third Eye. The group made one album before Ollie decided to concentrate on instrumental electronic music, and as a result the label undefined was founded, with Third Eye's second album Ancient Future as its first release. Ollie worked as A&R for Psy-Harmonics, as well as producing many of its releases. His collaborations with other musicians include The Visitors, Psyko Disko, Fluro Conspiracy, Higher Spin States, Assasin Device, Shaolin Wooden Men, and many others.

On Ollie's solo album, Emptiness, and in new material released in 2020, Ollie returned to his roots in avant-garde / experimental composition.

Besides work at Psy-Harmonics, Ollie also lectured on electronic music and composed for film and television; credits include the feature film "Head On"(1998) (which earned him an AFI nomination), "RAW FM" (1997) and "Eugénie Sandler P.I." (2000) both for ABC TV. He collaborated on interactive projects with [a1587441] and worked on the electronic component of Australian composer [a2190647]'s opera, "Batavia" (2001).

Ollie continued to stage live experimental music performances and occasionally guested with the Australian Art Orchestra. In 2002, he collaborated on a major orchestral project with AAO Director Paul Grabowsky.

In 2020 Olsen was diagnosed with multiple system atrophy (MSA), which was announced publicly in June 2023.