His first named role was on Werewolf, a horror series that ran during Fox's inaugural broadcasting year of 1987–1988.

[1][2][3] Thompson has played several characters in the Star Trek franchise—the most notable being the Klingon Lieutenant Klag in which he informed Commander William Riker that "Gagh is always best when served live", the Alien Bounty Hunter on The X-Files, and Eddie Fiori on Kindred: The Embraced.

He attended Central Washington University, where he studied business management, played football, and appeared in many school productions.

Thompson's athletic build and unique facial structure were key in the initial roles he was offered.

The New York Times wrote of Thompson's portrayal, "the archvillain, a character that is a cross between a James Bond fantasy villain such as Jaws and a raging psychopath, delivers a scorching monologue – a feat of linguistic sophistication that Cobra would have a hard time matching.

"[12] The following year, Thompson began his tenure on The X-Files and followed that with roles in the science fiction-fantasy series Seven Days, Buffy the Vampire Slayer and Charmed.

[14] Thompson then returned to the big screen as lead antagonist Shao Kahn in the poorly received Mortal Kombat Annihilation.

[15] The New York Times called it "colossal compendium of logic-defying martial arts, noisy, hyperactive special effects..."[16] In 2014, Thompson released The Extendables, a film he produced, wrote, and starred in.

Thompson has since participated in Star Trek fandom, giving narrative DVD extras and appearing at conventions.