From the 1990s he was seen as a guest star in various American television series, such as Charmed and ER.
[1] Greenquist was director Steven Soderbergh's preferred choice for the role of Graham Dalton in Sex, Lies, and Videotape, after Kyle MacLachlan and Aidan Quinn turned down the role.
However, the producers wanted a more well-known actor, so Soderbergh cast James Spader instead.
On Star Trek: Voyager, Greenquist appeared in the Season 3 episode "Warlord."
He played the thief Krit in the Star Trek: Deep Space Nine sixth season episode "Who Mourns for Morn?"