First elected to parliament at the 1990 Fremantle state by-election, McGinty became a minister in the Labor government of Carmen Lawrence in 1991.

In Opposition, McGinty succeeded Ian Taylor as Labor leader in 1994, only to be replaced by Geoff Gallop prior to the 1996 state election.

Most significantly he served for seven and half years as Attorney-General in the Labor governments of Geoff Gallop and Alan Carpenter.

Following Labor's defeat at the 2008 state election, speculation among media and political commentators was that McGinty, by then almost 60 years of age, would resign his seat before the end of the term.

Carles later quit the party to sit as an independent after the publication of an affair with Liberal treasurer Troy Buswell.