He studied at Auckland University from 1963–67. With a QEII Arts Council grant he attended the Ferien Kurse fur Neue Musik, Cologne and Institute of Sonology, Utrecht, Netherlands (1969–70). For two years (1976–77) he was a guest lecturer at the Akademi Musik Indonesia, Yogyakarta and since 1980 he has lectured at the School of Music, Victoria University of Wellington.
His music covers almost all genres, including solo and chamber music, orchestral music, music-theatre, music for dance and film as well as electroacoustic music. A fascination with the music and cultures of Asia, particularly Indonesia, has been a strong influence on his music. His ethnomusicological recordings include Music for Sale: Street Musicians of Yogyakarta (OMCD 006, and TC HLS-91), Music of Madura (CD ODE 1381) and Jemblung: Sung Narrative Traditions (PAN 2048CD).
His music has been played widely and by such performers as Lontano, Kronos Quartet, ARC, the New Zealand String Quartet, the New Zealand Symphony Orchestra, the BBC Symphony Orchestra and so on. He also works in experimental photography and computer-controlled sound-image installations, having received commissions from several public galleries. His opera Alley was premiered to wide acclaim at the 1998 New Zealand International Festival of the Arts. But his composition best known to the New Zealand public is the 1975 theme to the TV sitcom, Close to Home.
As a promoter of New Zealand music he has organised a series of Sonic Circuses, simultaneous multi-venue music marathons. He is the Director of Waiteata Music Press which publishes scores of New Zealand music, and has edited numerous CDs of New Zealand music. Jack Body was artistic director for the Asia-Pacific Festivals and Conferences in 1984 and 1992, which focused on the music (traditional and contemporary) of New Zealand and its Asia-Pacific neighbours.
Recordings of his music include Suara (Ode CD Manu 1380), electroacoustic compositions using field recordings from Indonesia, Sacred and Profane (Ode Portal CD 1004), three large scale works for voices and Pulse (Rattle D009), a series of five works based on transcriptions from traditional music. Pulse won the 2002 New Zealand Music Award for Best Classical CD and in 2003 Waiteata Music Press released a Composer Portrait on CD.
In 1985 he received the Composers' Association of New Zealand Citation for Services to New Zealand music and in 2001 he was honoured with an OMNZ in the New Year's Honours. In 2004, the Arts Foundation of New Zealand presented him with a Laureate Award.