Giles was created at the 1991 electoral redistribution to replace the abolished seat of Whyalla. It covered an area that had traditionally been a Labor stronghold, with support for the party being particularly strong in the city of Whyalla as well as in remote mining towns and indigenous communities. Sitting Labor MP for Whyalla and incumbent government minister Frank Blevins won his seat at the 1989 election with a safe 10.9 percent two-party margin. However, upon the creation of Giles, the margin was slashed in half to a notionally marginal 5.2 percent two-party margin. Labor suffered a swing in Giles at the 1993 election landslide, reduced to a 2.4 percent two-party margin for Labor successor Lyn Breuer. She subsequently increased Labor to a fairly safe to safe margin at subsequent elections before resigning from politics at the 2014 election, with Labor candidate Eddie Hughes retaining the seat.