He was a surveyor in private practice and managing director of a surveying and mapping consultancy before entering politics.

[2] He was the President of the Country Liberal Party between 1990 and 1994, during which time the CLP won two elections with an increased vote.

In January 2006, he was promoted to the front bench as Special Minister of State which included responsibilities with Ministerial and Parliamentary Services, the Australian Government Information Management Office, Australian Electoral Commission, Defence Housing Authority, and Film Australia.

In the 2007 federal election, Nairn lost his seat to Labor candidate Mike Kelly.

In September 2007, Nairn's chief of staff, Peter Phelps, engaged in a heated verbal exchange with the Labor Party candidate for Eden-Monaro, Mike Kelly at a forum on the Iraq War in Queanbeyan, New South Wales.

At the meeting Phelps claimed that Mike Kelly was a hypocrite as a former soldier running for the ALP when they are opposed to the war in Iraq.

[7][8][9][10] Nairn, in his role as Special Minister of State, announced the establishment of ASC, with initial membership including ANZLIC, ASIBA and CRC-SI.

ASC was reported as being established “to accelerate the unlocking of the potential of spatial information for economic, environmental and social benefit for Australia within key industries, and the development of tools, new technologies and capabilities relating to the fundamental future needs of the nation.” The actual role and achievements, if any of ASC, remain vague.

[11] Under the National Spatial Information Industry Action Agenda, the CRC-SI was established in 2003 and launched by Nairn after significant advocacy by ANZLIC led by Watkins and also ASIBA.