He had originally planned to retire at the 2008 election, but after the troubled seven-month leadership of Troy Buswell and generally poor opinion polls, Barnett was persuaded to reconsider (the nominated candidate for Cottesloe, Deidre Willmott, stood aside), and regained the leadership on 6 August 2008 on a unanimous party vote, one day before the 2008 election was called.

He resigned later in 2018, and businessman David Honey easily retained the seat for the Liberals with a healthy swing in his favour.

As at the 2007 redistribution, Cottesloe is bounded by Loch Street and Brockway Road to the east, Perry Lakes and Bold Park to the north, the Indian Ocean to the west, and the Swan River to the south and southeast.

Prior to the redistribution, it had additionally contained sections of City Beach and Floreat, which were moved north into neighbouring Churchlands.

Cottesloe and the neighbouring electorates of Churchlands to the north and Nedlands to the east comprise the affluent western suburbs of Perth—the Australian Bureau of Statistics's SEIFA index (2001) ranked them as the highest three electorates by socio-economic status in Western Australia, with high scores on educational and employment opportunity.