Marshall joined the Bristol music scene as a member of the DJ group The Wild Bunch in the 1980s, which included two other Massive Attack members, Robert Del Naja and Andrew Vowles. In 1986, The Wild Bunch dissolved. Del Naja, Vowles, and Marshall then formed the trip-hop group Massive Attack, which is considered to have pioneered the "Bristol Sound" along with Portishead and Tricky.