Christos was born in Melbourne, the city with the largest Greek population outside Athens, to Greek immigrant parents who were both factory labourers. He was raised in an inner-city Greek district.

He attended Melbourne University and completed a BA in 1987. That year he also became editor of the student newspaper Farrago, later contributing to and co-designing the literary Arena magazine. Since then he has worked a variety of jobs but remains committed to a career in writing with occasional forays into Super-8 film-making.

His first semi-autobiographical novel is the gritty Loaded (1995), an insightful exploration of 24 hours in the life of a young alienated and nihilistic bisexual working class man from an immigrant minority culture. The book is loaded with uncompromising and frequently shocking language, and is filled with rough sex, hard drugs, and popular film and musical references.

Loaded was followed by The Jesus Man (1999), then by Dead Europe, dealing with ghosts of anti-Semitism within Greek culture. Christos co-authored Jump Cuts: An Autobiography (1996) and many of his short stories have also been published. His acclaimed plays include "Whose Afraid of The Working Class?", "Blue Poles" and "Elektra AD." He co-made the short film Thug that appeared on SBS's "Eat Carpet" series in 1998.

The highly successful film Head On (1998) is based on Christos' Loaded and stars young Greek-Australian heart-throb Alex Dimitriades as Ari and gay diva Paul Capsis as Johnny/Toula. Tsiolkas currently co-edits the alternative literary publication "Refo." He has been in a committed relationship with his boyfriend since the mid-1980s.