[2] Prior to entering politics she worked as an organiser for the Federated Liquor and Allied Industries Employees' Union of Australia (1980–1982), employment officer for the Commonwealth Employment Service (1982–1983), and as women's organiser (1983–1984) and state industrial officer (1984–1988) for the Public Sector Union.
After leaving her union job she served as a senior adviser to Tasmanian Labor parliamentarians, including federal MP Duncan Kerr (1988–1990), state health minister John White (1990–1992) and opposition leader Michael Field (1992).
[1] In March 1996, Mackay was appointed to the Senate to fill a casual vacancy caused by the resignation of John Devereux.
[1] Mackay announced her retirement from politics in July 2005, citing the ill health of her partner as well as "the impending change in numbers in the Senate" (the Howard government's new majority status).
She stated that she left parliament "with a real sense of apprehension at the unfettered power of the executive with none of the checks and balances that the Senate has provided".