He made guest appearances on all three of the longest running North American science fiction series: The X-Files (1993), Stargate SG-1 (1997) and Smallville (2001).
Sebastian has 1 older sister, Sarah, 1 younger half brother, Fergus and 1 younger half-sister Perdita. His father was playwright Michael Cook. His mom was playwright and actress Janice Spence.
Son of playwrights Janis Spence and Michael Cook.
Lives in Vancouver, British Columbia, Canada with wife and step children.
Plays the guitar.