 Jeff Duff began his musical career in Melbourne in 1971 as lead singer of jazz-rock fusion band Kush (1971–75)

Kush was formed with Jeff Duff on vocals, John Santos (aka Montesante) and Colin Chapman on trumpet, Ron Anderson on piano and saxophone, Stephen Ball on keyboards, Tom Cowburn on guitar, harmonica and backing vocals, John Ellis on clarinet, flute and saxophone, Rob Matthews on bass guitar, and Graham McDonald on drums.They released covers of "Peter Gunn", "MacArthur Park" and "Walk on the Wild Side" as well as originals such as "(Livin' on) Easy Street"

Kush are notable for performing to 45,000 people at the 1974 Sunbury Pop Festival, "conceived and promoted as Australia's Woodstock".Duff relocated to London in 1978 as "the waif-like androgynous oddball Duffo" His keyboard player and arranger for most of this period was Sev Lewkowicz.