It was triggered by the resignation of Bill Hassell (the sitting Liberal member and former leader of the opposition) on 28 June 1990.
The Liberal Party retained Cottesloe at the election with an increased majority, with Colin Barnett (an economist) securing 70.26 percent of the two-party-preferred vote.
Bill Hassell had held Cottesloe for the Liberal Party since the 1977 state election.
He remained in the shadow ministry until shortly before his resignation from parliament, which occurred on 28 June 1990.
He led the party from 2001 to 2005 without electoral success, but was re-elected leader prior to the 2008 state election and subsequently became premier, a position which he held until 2017.