 She became a union official and regional secretary of the Miscellaneous Workers' Union and worked as an electorate officer to Jennie George, the Federal Member for Throsby.In 2002, she won ALP preselection from the sitting member, Col Markham, and was the first woman elected for the seat of Wollongong.Following the 2007 election, Hay was appointed Parliamentary Secretary to Health Minister Reba Meagher.