Gareth Farr began his studies in composition and percussion performance at Auckland University. The experience of hearing a visiting gamelan orchestra prompted his return to Wellington to attend Victoria University, where the characteristic rhythms and textures of the Indonesian gamelan rapidly became the hallmarks of his own composition. He continued with postgraduate study in composition and percussion at the Eastman School of Music in Rochester, New York, where his teachers included Samuel Adler and Christopher Rouse.

In 1993, at the age of 25, Gareth was appointed composer-in-residence by Chamber Music New Zealand, the youngest-ever composer to hold that position. This resulted in the composition of three substantial works, Owhiro (String Quartet No. 1), Kebyar Moncar (for gamelan) and the chamber sextet Cadenza. At the conclusion of the residence, Gareth returned to the Eastman School to begin a doctorate in composition. As well as composing Kembang Suling (for flute and marimba, his most popular work to date) and three works for orchestra during this time, Gareth also introduced audiences to his on-stage alter-ego, the percussion-playing drag queen Lilith Lacroix.

The inclusion of his works in four events at the 1996 New Zealand International Festival of the Arts - the ballet score for Douglas Wright's Buried Venus, Lilith's Dream of Ecstasy, for orchestra, Kembang Suling, and the Bach-in-Bali piano solo Sepuluh Jari - kick-started his career as a dedicated freelance composer. Since then, his music has been heard at, or especially commissioned for, high-profile events including the 50th anniversary of the New Zealand Symphony Orchestra (the 25-minute From the Depths Sound the Great Sea Gongs), the opening of the Museum of New Zealand Te Papa Tongarewa (Te Papa, a work hailed as ‘music with a powerful and moving impact that transcends idiom and individual taste'), and the 2000 Olympic Games in Sydney (Hikoi, a concerto for percussionist Evelyn Glennie and the New Zealand Symphony Orchestra). Most recently, a commission by the 2003 Auckland Festival resulted in Stone and Ice, composed for the combined forces of the New Zealand Symphony Orchestra and the Auckland Philharmonia Orchestra. In 2006 Gareth was made an Officer of the New Zealand Order of Merit, for his services to music and entertainment.

Gareth Farr's music is particularly influenced by his extensive study of percussion, both Western and non-Western. Rhythmic elements of his compositions can be linked to the complex and exciting rhythms of Rarotongan log drum ensembles, Balinese gamelan and other percussion music of the Pacific Rim.

In addition to his music for the concert chamber, Gareth has written music for dance, theatre and television. In 2003 he won the Chapman Tripp theatre award for his soundtrack to Vula - a New Zealand/Pacific Island theatre piece - that went on to perform extensively overseas including Australia, the Netherlands and London.

In 2006, the Royal New Zealand Ballet toured the country with their brand new work The Wedding, featuring a score by Gareth Farr. At 90 mins, it was among the ballet company's most ambitious projects, and brought Gareth together with prominent New Zealand novellist and fellow-Laureate, librettist Witi Ihimaera.

Gareth's music was integral to Maui - One Man Against the Gods, a stage show four years in the making. First premiered in 2003, in incomplete form, it featured aerial theatre, Maori kapa haka, contemporary dance and song, with Gareth's stirring music touring a number of centres in New Zealand.

In 2006-08, Gareth developed a fruitful collaboration with director and librettist Paul Jenden, producing three comedy musicals. Troy is a witty retelling of the classical myth, Monarchy a romp through the history of the British Monarchy and Rome an evening at home with the Caesars.

In 2007 Farr was appointed as Composer-In-Residence for the Auckland Philharmonia Orchestra culminating in 2008 with the premiere of Ex Stasis a symphonic song cycle for four soloists. In 2008 Farr also celebrated the world premiere of his new work Terra Incognita, for bass baritone solo, choir and orchestra, performed by Paul Whelan and the Orpheus Choir with the New Zealand Symphony Orchestra, conducted by Paul MacAlindin.

Gareth Farr has an alter ego, Lilith Lacroix. Lilith has been a cast member of the Life's a Drag female impersonation show at Club Marcella New York; was named Miss Sweetheart 1995; 1st runner up Miss Gay Upstate New York 1995 and 2nd runner up Miss Gay Rochester 1995. She has performed at various venues in New Zealand, including as part of the New Zealand International Festival of the Arts and has appeared in the Hero, Devotion and San Francisco Gay Pride parades. She has performed her solo show DRUMDRAG to sold-out houses, won a fashion award at the Trentham Races wearing her own high-fashion handiwork and appeared in television commercials.

Gareth received an Arts Foundation of New Zealand Laureate Award in 2010.