Metcalfe's unique style is a result of his extensive experience in classical, pop and electronica. Early musical influences include opera (his father was an operatic tenor), the post-punk group Joy Division, and the avant-garde electronic band Kraftwerk. As a violist he co-founded the Duke Quartet which quickly developed a reputation as one of the UK's most exciting ensembles. The ensemble has released many CDs and tours worldwide. Metcalfe’s string arrangements played by the Dukes feature on many albums by pop artists including Morrissey, Simple Minds, The Pretenders, Catatonia and Blur. The commercial success of Metcalfe's first two albums of original music has led directly to several new commissions for TV and the concert hall.
He started playing the viola after moving to the UK from New Zealand in 1972. Later, he joined Vini Reilly in the Durutti Column. During this period, he also studied viola at the Royal Northern College of Music and later at the Hochschule in Berlin.
Metcalfe was instrumental in the formation of the record label Factory Classical, an offshoot of Tony Wilson's Factory Records. He also wrote string arrangements for various popular artists, including Morrissey, Simple Minds and The Pretenders. He released an album of his own, The Inner Line, to positive reviews. In 2004, another album, Scorching Bay, was released, followed by "A Darker Sunset" in 2008. A new John Metcalfe album, 'The Appearance of Colour' was released on April 2013 as part of Bowers and Wilkins Society of Sound subscription series.
Recent commissions include a set of pieces for the guitarist Tom Kerstens and an album of electronic/acoustic music for 'cellist Matthew Barley. His music has also been used by various contemporary dance companies.
Since 2010, he has been working with Peter Gabriel, writing arrangements for his "song-swap" album, Scratch My Back, and for the tour following it. For New Blood (2011), which he co-produced with Gabriel, he arranged and orchestrated versions of Gabriel's songs.
In 2015, Metcalfe released a solo album titled The Appearance of Colour on Real World.