Alongside Jack Body, Gillian Whitehead and John Psathas, Farr is one of the noted New Zealand composers.
Farr was born in Wellington in 1968. He began his studies at the University of Auckland in composition, orchestration and electronic music. While studying there, he performed as a member of the Auckland Philharmonia Orchestra (APO) and the Karlheinz Company. Returning to Wellington in 1988 for further study at Victoria University of Wellington, he gained note for his compositions, at this time becoming increasingly excited with exploring the Indonesian gamelan. He played percussion frequently with the NZSO before going to the Eastman School of Music in Rochester, New York for advanced study.
Farr became the composer-in-residence with Chamber Music New Zealand at 25, the youngest person to hold that post. In 1994, he had four works commissioned for the 1994 International Festival of the Arts including Lilith's Dream of Ecstasy and works for flautist Alexa Still and pianist Michael Houstoun as well as a ballet. In 1996 he signed to music publisher Promethean Editions becoming a founding house composer.
His work From the Depths Sound the Great Sea Gongs was specially commissioned for the 50th anniversary of the NZSO. Farr also wrote an orchestral piece Te Papa for the opening of Te Papa, the National Museum of New Zealand, in 1998.
In 2000, the NZSO performed his percussion concerto Hikoi with Evelyn Glennie at the Sydney Olympics. He has released four CDs of his work on the Trust label with the fifth, Ruaumoko released in early 2006.
In 2005, he provided the music for Vula staged during the Christchurch Arts Festival prior to the world debut of his Triple Concerto performed by the New Zealand Trio and Christchurch Symphony Orchestra. During 2006, New Zealand premieres of Farr's music included Funambulistic Strains for orchestra and trombone, performed by David Bremner and the NZSO, The Wedding for the Royal New Zealand Ballet, and TROY the Musical with librettist Paul Jenden.
In December 2005 Farr visited Antarctica as part of Antarctica New Zealand's artist programme. The result of the two week residency was a piece for baritone singer and orchestra inspired by the ill-fated last expedition of Robert Falcon Scott. The work was performed in 2008 by London based New Zealand singer Paul Whelan and the NZSO.
In 2008, Gareth was appointed Composer-in-Residence of the APO. Farr composed a memorial piece for the Christchurch earthquake, Nor'West Arch, first performed on 25 September 2011. The title makes reference to a particular Christchurch weather pattern, but is also that part of the ChristChurch Cathedral that received most damage in the earthquake. Dean Peter Beck was part of the performance, reading out an introduction and a reflection. The concert was one of the highlights of the 2011 Christchurch Arts Festival.
Gareth Farr also performs in drag as Lilith LaCroix in cabaret shows. Since 1997, the cabaret Drumdrag features Lilith playing the drums and Farr has recorded a CD released under her name. LaCroix also made a music video to promote the album.
Farr promotes himself as an entertainer as well as a composer:
I would, perhaps, be criticised for being too entertaining by some composers, but I don't know what's wrong with that because that is why I write music—I'm an entertainer. That's a dirty word in the classical department, but I don't care. I've even got it on my business card — composer/entertainer — because, hey, let's face it, that's what I do.
Farr was made an Officer of New Zealand Order of Merit in the 2006 Queen's Birthday Honours List for services to music and entertainment.