Rooney grew up in Ringsend, Dublin and started his career in the Irish Government sector with various roles in the Postal, Telecoms and Civil Aviation sectors. After meeting the well-known Irish businessman Dermot Desmond he worked in one of Desmond's investments, Quay Financial Software. Following restructuring the company was sold to a major Japanese corporation in 1995. Following this he was Managing Director of Meridian Vat Processing Limited, another of Desmond's investments start-up company that was successfully developed and sold a number of years later.
Desmond, Rooney and Michael Smurfit then acquired Baltimore Technologies, and Rooney served as CEO from 1996-2001. He pulled off a big coup in 1998 when Bill Clinton and Bertie Ahern signed an Electronic Commerce deal using Baltimore's technology, a marketing opportunity which Baltimore made great use of. Under Rooney's leadership Baltimore underwent several successful mergers, became a member of the FTSE 100, and was also successfully listed on the NASDAQ. Baltimore experienced a precipitous fall in its valuation following the dot-com crash and Rooney left the company.
He was Chief Executive Officer of the Football Association of Ireland from May 2003 to November 2004. He is currently Executive Chairman and major shareholder of ICE Broadband, a company founded by 3 Telecommunications Engineering students of Dublin City University, whose CEO is currently his eldest daughter Yvonne Rooney In September 2005, under his Chairmanship, Vimio plc successfully listed on the AIM Market in London.
He and his companies have received many awards for achievements in business. The President of Ireland, Mary McAleese, presented Mr. Rooney with the Businessman of the Year award in 2000. He was Bank of Ireland Entrepreneur of the Year in 2001. Baltimore Technologies was Company of the Year in 1998 and 2000.
Mr. Rooney is a Fellow of the Institute of Chartered Accountants, a Fellow of the Irish Computer Society and a member of the Institute of Internal Auditors. He also has qualifications in Law from Kings Inns, Information Technology and Administrative Science. He is a member of the Board of the People in Need Trust
He played for Shamrock Rovers and coached football and Gaelic Football teams. He would come to say that 'Sport is the greatest character builder of all'. He continued to play football and became a football manager eventually managing the Irish Women National Team Manager from 1986 - 1992.He recently Coached the under-age side at Coolmine Rugby Club. He holds a Black Belt in Kickboxing and has also trained in Taekwondo.