Dr Mahoney graduated from The University of Queensland in 1974, before training in anatomical pathology at the Mater and Princess Alexandra Hospitals, Brisbane. In 1984 she joined QML Pathology as a pathologist and is currently in Charge of the North Lakes Laboratory, where she specialises in histopathology.

Dr Mahoney continues to be an active member of the Australian Medical Association (AMA) and previously spent two years on the branch council in Queensland, including one year as state secretary. She has also acted as secretary of the Redcliffe and Districts Local Medical Association.