Greg Phillips started his career in 1976 at Port Adelaide and was a key member of their defence during a successful era for the club. He was a member of eight Port Adelaide premiership sides, in 1977, 1979, 1980, 1981, 1988, 1989, 1990 and 1992. At the 1980 Adelaide State of Origin Carnival he was selected in the All-Australian team.
Phillips joined VFL club Collingwood in 1983 and played with them for four seasons before returning to Port and winning their 1988 best and fairest. Phillips was captain of Port Adelaide from 1991 to the end of the 1993 season, when he announced his retirement.
In 2000 Phillips was selected as a centre half back in Port Adelaide's official 'Greatest Team 1870 to 2000'.