In the late 1960s and early 1970s the composite kind of jazz-rock fusion was developed by mixing jazz improvisation with rock rhythms, electrical instruments, and the highly intensified stage sound of rock musicians such as Jimi Hendrix. All Music Guide states that "..until around 1967, the worlds of jazz and rock were virtually absolutely separate." But "...as rock became more creative and its musicianship improved, and as some in the jazz world became bored by hard bop and didn't wish to play exactly fashionable music, the 2 different idioms started to trade ideas and infrequently mix forces." Miles Davis made the discovery into fusion in 1970s with his album Bitches Brew. Musicians who worked with Davis formed the 4 most influential fusion groups : Weather Report and Mahavishnu Orchestra appeared in 1971 and were shortly followed by Return to Forever and The Headhunters. Though jazz purists demonstrated the mix of jazz and rock, some of jazz's serious trailblazers crossed over from the recent hard bop scene into fusion. Jazz fusion music frequently uses mixed meters, strange time signatures, syncopation, and complicated chords and harmonies.

As well as using the electrical instruments of rock , for example the electrical guitar, electric bass, electrical piano, and synthesizer keyboards, fusion also utilised the strong amplification, "fuzz" pedals, wah-wah pedals, and other effects utilized by 1970s-era rock bands.Outstanding performers of jazz fusion included Miles Davis, keyboardists Joe Zawinul, Chick Corea, Herbie Hancock, vibraphonist Gary Burton, drummer Tony Williams, violinist Jean-Luc Ponty, guitarists Larry Coryell, Al Di Meola, John McLaughlin and Frank Zappa, sax player Wayne Shorter, and bassists Jaco Pastorius and Stanley Clarke. Jazz fusion was also favored in Japan where the band Casiopea released over 30 albums praising Jazz Fusion.