He was born in Bingara, New South Wales, and was educated at the Shore School, where he was School Captain and Captain of the GPS Rugby 1st XV, Sydney University, where he resided at St. Paul's College, and Oxford University, where he gained an MA and was selected as a Rugby Blue against Cambridge.

[5] Following his preselection loss, on 3 September 2004 King announced that he would stand for Wentworth as an independent at the 2004 election.

His wife Fiona, daughter of former National Party leader Ian Sinclair, was banned for five years.

In August 2017 King and lawyer Matthew Bransgrove formed an organisation called CivilDefenceNow and began a series of lectures to Liberal Party branches in the Wentworth electorate on the dangers posed to Australia's national security by North Korea.

[13] He is the author of Limitation of Liability in Australian Maritime Law (1991), and a critique of climate change policy called The Challenge of the Commons (2015).