Stack previously worked as an assistant governor in the Irish Prison Service and recently launched a new health and safety consultancy business in Portlaoise. In 1983, his father Brian Stack, a prison officer in Portlaoise Prison, was shot in the neck by the IRA as he left an amateur boxing contest in the National Stadium in Dublin. He died in hospital 18 months later. Austin Stack was 14 at the time of the attack and he has campaigned for many years for justice for his father’s murder.