 Cull was first elected to the legislature in a by-election held on December 13, 1989, defeating Social Credit candidate Susan Brice and becoming the first New Democrat to win Oak Bay-Gordon Head.She was re-elected on October 17, 1991 in the subsequent provincial general election.In 1991, Cull was appointed Minister of Health in Premier Mike Harcourt's first cabinet, the first woman to be named to the position.