Subtitling itself as Television Without Borders, Showcase was licensed in 1994 to Alliance and began broadcasting in 1995. Notable for the frequency with which its predominantly fictional programming required viewer discretion advisories, the channel originally had the CBC as minor shareholders, and providing programming in lieu of their financial obligations, but the channel later became 100% owned by Alliance Atlantis.
While the basic Showcase schedule consisted of reruns of major Canadian and US drama series, the channel was constantly pushing the envelope with its acquisition and broadcast of more risqué material, which helped to make it one of the most popular of the specialty channels available by cable and satellite.
In 2001, Showcase introduced a new Canadian series, Trailer Park Boys, which was to run very successfully for over seven years. Originally a series spin-off from a movie of the same title, Trailer Park Boys became Showcase's highest rated Canadian series, and was sold widely throught the world. It won several awards in Canada.
CanWest Media Networks acquired Alliance Atlantis in December 2007, and with it ownership of Showcase.
In June of 2009, CanWest announced that a new-look, new logo Showcase would be introduced to viewers on August 31st. Similar facelifts were promised for the companion specialty channels Showcase Diva and Showcase Action , including a name change for the latter channel, which would simply be called Action.
On November 14th 2009, the Acadamy of Canadian Cinema and Television presented a special Gemini Award to Trailer Park Boys, with the following citation:
"Trailer Park Boys follows the story of Ricky, Julian and Bubbles - three guys whose view of the world has been shaped by their experiences growing up in Sunnyvale Trailer Park. First introduced to Showcase viewers in 2001, it quickly grew into a ratings success and pop culture phenomenon. The series became the highest-rated Canadian show on specialty television in 2004 and won Gemini Awards for Best Comedy Series (2004) and Best Ensemble Performance in a Comedy Series (2005). Several famous recording artists have appeared on the show, including Alex Lifeson of Rush, singer Rita MacNeil, Brian Vollmer of Helix, Sebastian Bach of Skid Row and singer/songwriter Denny Doherty".
In July 2010 Christine Shipton, CanWest's Senior Vice-President of Drama and Factual Content announced that, as part of the rebranding of Showcase as "a really mainstream drama channel", a new mini-series, The Kennedys, would be filing during the summer in Cobourg, Hamilton and Toronto, Ontario. Other new series to play on Showcase during the summer would include Haven, a coproduction with the US company Syfy, and Blackstone, set on a Canadian native reserve.
In 2010, Shaw Communications acquired CanWest. In 2016, Shaw Media was acquired by Corus Entertainment.