Cameron Stewart is originally from Toronto, Canada, where he grew up, as well as spending several years of his youth in the United Kingdom.
His first published comics work was in 2000, illustrating issues of Scooby Doo and Superman Adventures for DC Comics, while also working as a storyboard artist on the third season of the Men In Black animated television series. Shortly after he drew a small sequence in Grant Morrison's The Invisibles, and was regular inker on Ed Brubaker's Deadenders. He worked with Brubaker again as artist of Catwoman in 2003, and from there illustrated the first of Morrison's wave of Vertigo miniseries, Seaguy.
In 2006 he collaborated with Morrison again on one of his interlocking Seven Soldiers of Victory miniseries, The Manhattan Guardian. Following that he worked with then-newcomer Jason Aaron on his first series, the Vietnam war story The Other Side, for which he travelled to Vietnam for research, and was nominated for a 2007 Eisner Award for Best Limited Series.
In 2007 he worked as inker on the Vertigo series The Vinyl Underground, while fully illustrating The Apocalipstix from Oni Press, co-created with writer Ray Fawkes. He followed that with a sequel to 2003's Seaguy, entitled Slaves of Mickey Eye.
2010 saw yet another collaboration with Grant Morrison on Batman & Robin, and he co-wrote and illustrated Assassin's Creed: The Fall, an original graphic novel based on the series of video games. He also won the 2010 Eisner Award and the 2010 Shuster Award for Best Digital Comic, for his ongoing webcomic Sin Titulo, which was also nominated for Eagle and Harvey Awards.
In 2011 he illustrated Batman Incorporated: Leviathan Strikes!
Recently he has completed another Assassin's Creed graphic novel (with co-creator Karl Kerschl), wrote and drew 2 issues of BPRD: Hell On Earth: Exorcism, and is now working to complete Sin Titulo for print publication.
He currently lives in Berlin, Germany.