Wills played 1966-1968 with David Gilmour and Dick Parry in the blues-rock band " Joker's Wild". When the band broke up after the departure Gilmour on Pink Floyd, he was bassist for Peter Frampton, with whom he worked until 1975. After he was briefly a member of the Small Faces in 1977, he joined Foreigner in 1979. Wills was until 1992 a total of 14 years, the band's bassist. After leaving Foreigner, he was until 1998 a member of Bad Company.
The mid-2000s he was a member of Jones transition to Kenny Jones.