Morialta is derived from a Kaurna Aboriginal word "mariyatala", with "mari" meaning east and "yertala" meaning water. The land used by the Morialta Conservation Park was traditionally occupied by the Kaurna people. Morialta was the new name adopted at the 2002 election for the old electorate of Coles, which was first created at the 1970 election and represented over the years by several distinguished MPs, including former Dunstan Attorney General Len King and former Premier Des Corcoran. Morialta was won at the 2002 election by Liberal minister Joan Hall on a margin of 4.1 percent, suffering a 2.4 percent swing. The boundary redistribution prior to the 2006 election saw the Liberal margin decline by approximately 0.7 percent. Hall was thought likely to again hold the seat with a reduced margin, but was defeated by Labor candidate Lindsay Simmons amidst a statewide landslide, receiving a 12 percent two-party swing to finish with a 7.9 percent margin. However, the 2010 election saw the seat swing 11.1 percent back to the Liberals, with candidate John Gardner defeating Simmons on a margin again of 4.1 percent.