Initially appearing in the "Pilot" as an extra with no lines, Davis' role as the Cigarette Smoking Man developed into an integral part of the show, becoming involved with the major storylines.
William B. Davis was born on January 13, 1938 in Toronto, Ontario, Canada. He graduated in philosophy at the University of Toronto in 1959. Davis turned to acting and directing and joined Britain's National Theatre in 1964, working with Maggie Smith and Laurence Olivier. He returned to Canada the following year to become first Assistant Artistic Director and subsequently Artistic Director of the National Theatre School of Canada in Montréal, Quebec.
In 1989, Davis opened the William Davis Centre for Actors' Study in Vancouver, British Columbia. Beginning in the mid-nineties, acting began to dominate his working life, highlighted by the iconic role of the X-Files' Cigarette-Smoking Man. Besides David Duchovny and Gillian Anderson, he is the only actor to appear in both the pilot and the original series finale. He can also be seen in the science-fiction series The Outer Limits, Stargate SG-1, Smallville and Supernatural. Feature films include The Messengers and The Tall Man. Davis has been married to Emmanuelle Herpin since 2011.