Tierney dropped out of art school, moved out of home and shifted into the bFM recording studio, with his clothes and bedding tucked away in the corner of the vocal booth. Having a studio at his disposal allowed him and Casserly unlimited time to play around and led to Hemisphere, their 1990 debut album as Strawpeople, on Pagan Records.

Around the same time Tierney met producer Alan Jansson and started working at his studio Module 8, learning more about electronics and began picking up freelance engineering work around town.

Tierney next took up the role of in-house engineer at The Lab studio in Symonds St in early 1991 after the departure of Terry Moore (to re-join The Chills), working for studio owner Bill Lattimer. While there he recorded a diverse range of acts such as SPUD, Hallelujah Picassos, MC OJ and the Rhythm Slave, Matty J Rhys, and the Greg Johnson Set.

Tierney was a key partner in setting up the influential Deepgrooves record label in 1991, along with Lattimer and Kane Massey. The label launched its first compilation in December of that year – a release that was recorded and mixed in nine days.

His role with the label was engineer, helming sessions for many of their artists, such as Fuemana, and many of the acts on the first two compilations from Deepgrooves. He left the label about two years later.

In 1991 Tierney set up Wireless studio with Casserly. Based in Queen Street, it produced the two Strawpeople albums World Service (1992) and Broadcast (1994). Tierney parted ways with Strawpeople in February, 1996, leaving Casserly to go it alone (although some of Tierney's contributions can be heard on the 1996 Strawpeople album Vicarious). Tierney sold the studio gear to Kane Massey and Deepgrooves.

Tierney also had a couple of high profile side careers in the late 80s and early 90s. He wrote film reviews for The Listener, and worked as a music TV show co-host on CV, TVNZ’s replacement for Radio With Pictures. He didn't much enjoy being in the public eye in this capacity.

In 1995 Tierney began shooting music videos and TV commercials  and with Casserly made several videos for the Strawpeople. Tierney made numerous music clips in 1996 for the likes of Bike, Jan Hellriegel, The Chills, Matty J, Stellar, Grace, The Exponents, and more.

Tierney shifted into A&R at PolyGram Records in September 1996, staying there until February 1999 when the Universal takeover of PolyGram made his job redundant.

Tierney then worked on a new online music retail site, Hyperactive, for the Sounds chain, but the concept was arguably before its time and was still-born.

He departed New Zealand in 2000 to make his name further afield. Since then he’s been based in Atlanta, Miami, London, Los Angeles, working as a filmmaker and photographer. While in London he directed the film Naked and started the 48 Hour Film Challenge. Tierney has worked for the BBC, Al Jazerra and Channel 4. He co-wrote and edited an award-winning documentary about Kurdish Iraq, Return to Kirkuk.

He is presently based in Los Angeles working mainly in TV and indie film. He’s recently been involved in making music videos for acts in the UK, US and New Zealand, notably Go Stop Go (featuring Matty J), and Jan Hellriegel.