Carides was born in Sydney, Australia, to a Greek father and an English mother. An actress since the age of 12, she has won awards for her films Strictly Ballroom and Brilliant Lies from the Australian Film Institute. She is best known for her roles as Robin Spitz Swallows in Austin Powers: The Spy Who Shagged Me and as Cousin Nikki in My Big Fat Greek Wedding and the television show My Big Fat Greek Life. Carides also starred as the character Helena Angelopoulos in the Southern Star Group Television show Police Rescue from 1992-1993.
Carides works in both America and Australia. She has volunteered as an actress with the Young storytellers program. Carides is married to actor Anthony LaPaglia, whom she met while jointly starring in the 1994 (Ben Lewin) Australian movie Lucky Break. She and LaPaglia are the parents of daughter Bridget (born in 2003). Gia Carides is sister to Zoe Carides, also an actress, and sister-in-law to doctor turned actor Jonathan LaPaglia (from New York Undercover).