[1] Cairns attended Christian Brothers' High School, Lewisham, and St Joseph's College, Hunters Hill.

He subsequently practised as a dentist for periods in Sydney, Melbourne, and Broken Hill, before settling in Brisbane in 1955 where he established a dental practice in Stones Corner.

[1] A member of the Liberal Party, Cairns made three unsuccessful bids for the Division of Brisbane in Queensland before finally being elected to the House of Representatives for the nearby seat of Lilley.

[2][3] Cairns worked as an economic consultant for the Queensland Tourist and Travel Corporation and Mount Isa Mines.

[1] Cairns was the uncle of Clare Martin, a Labor Party politician who was Chief Minister of the Northern Territory from 2001 to 2007.