Before entering politics Fitzgibbon was an automotive electrician, electorate officer, part-time technical education lecturer and small business operator. He was a member of the Cessnock City Council in the period 1987-95.
Fitzgibbon was elected to the Opposition Shadow Ministry in October 1998 and was Shadow Minister for Mining, Energy and Forestry in 2003-05. In June 2005 he was appointed Shadow Assistant Treasurer and Shadow Minister for Revenue and for Small Business and Competition.
In early December 2006, when Kevin Rudd became Leader of the Opposition, Fitzgibbon was appointed Shadow Minister for Defence.