Before her job at the BBC, Fairbairn had a varied career. She worked for seven years as a management consultant for McKinsey and Company. She also held a job with the Downing Street Policy Unit, developing policy for health and social services. She had worked as a financial journalist for The Economist, and as an economist at the World Bank.
Fairbairn came to work for the BBC as Director of Strategy for BBC Worldwide. It was after this that she was promoted to Director of Strategy & Distribution, and also became a member of the BBC's Executive Board. She helped to develop the BBC's digital strategy and renewal of their charter, and was instrumental in creating One BBC and Freeview.
On 10 June 2004, the BBC announced that Fairbairn and her husband "have decided to take time out from their careers to spend a year travelling around the world with their three children."
Fairbairn briefly rejoined McKinsey and Company in 2006, before becoming director of corporate development and strategy at ITV plc in March 2007.