Andrew Charles Farriss was born on 27 March 1959 in Perth, Western Australia, to Dennis and Jill Farriss, and is the second oldest of four children: he has two brothers, Tim (born 1957) and Jon (born 1961), and a sister, Alison. At the age of five years, Farriss, and his family had a holiday in London where they saw a performance by The Beatles. In 1971 the Farris family relocated to Sydney where he attended Davidson High School. With Tim taking up guitar lessons, Farriss "had instinctively taken to playing piano", and Jon played drums. At school Farriss met Michael Hutchence after preventing a fight with another student. The two became friends and in 1976 Hutchence, on lead vocals, joined his band, Doctor Dolphin. The line up included two other classmates, Kent Kerny and Neil Sanders and, from the nearby Forest High School a bass guitarist, Garry Beers, and Geoff Kennely.
Farriss is credited solely with keyboards on the band's earliest albums, but by 1984's The Swing, he was listed as playing guitar, as well. On stage, he also plays harmonica and various hand-held percussion instruments.
While INXS' early albums credit the band as songwriters, by their third album, Shabooh Shoobah, the team of Farriss as composer and Hutchence as lyricist was well established. While there were some INXS songs written by other members of the group, or by Farriss alone, it was this combination that brought INXS the majority of their international success in the 1980s and 1990s. In fact, Farriss co-wrote all of the band's top-40 hits in the US, except for "Disappear," which was written by Hutchence with Farriss' younger brother Jon, who is the band's drummer.
Despite extensive writing, recording and touring commitments with INXS, Farriss collaborated with many other Australian artists in a songwriting or production capacity. His most significant early collaboration was with Jenny Morris, a New Zealand singer who had sung back-up vocals on INXS' 1985 hit album, Listen Like Thieves. Farriss has also co-written and produced with the Australian Aboriginal band Yothu Yindi, Australian country singer Tania Kernaghan and Scottish rockers GUN. At the ARIA Music Awards of 1990 he won Producer of the Year.
In 2005, INXS launched a reality TV show, Rock Star: INXS, a worldwide search for a new lead singer. While all of INXS knew it would be impossible to replace Michael Hutchence, who died in 1997, they wished to carry on bringing their music to the world. Farriss was often seen as introverted compared to his band mates and he appeared shy to offer criticism to contestants. Canadian J.D. Fortune was the eventual winner, and the band's first album with Fortune, Switch, was released in late 2005.
Farriss met his first wife, Shelley Blanks, in 1987; they were married on 22 April 1989. The couple has three children: Grace, Josephine and Matthew.
In the official INXS autobiography Story to Story Farriss describes his dislike of touring and being away from his family.
On 4 October 2013, Farriss and his fiancée, Marlina, were wed at Cay Pointe Villa Resort in Indian Rocks Beach, Florida, USA.