[2] He has appeared in TV series Supernatural, Dollhouse,[3] the Showcase time travel show Continuum, and as the antagonist Darius in the 2006 racing video game Need for Speed: Carbon.

[11] In 2010, Penikett played the lead role of Matt Ellman on Syfy's miniseries Riverworld, an adaptation of the science-fiction books written by Philip José Farmer of the same name.

[12][13][14] He starred in the first two episodes of Warner Bros' Mortal Kombat: Legacy as Kurtis Stryker, which debuted in April on YouTube; he was replaced by Eric Jacobus for season 2.

[15] He portrayed a police officer for a predominantly gay neighbourhood in the 2004 The L Word episode "Losing It",[6] which also starred Battlestar Galactica co-star Nicki Clyne in a related storyline.

The production was filmed in Vancouver, British Columbia, Canada, and Penikett, a local actor, auditioned and was cast in the part of Karl "Helo" Agathon, an officer in the Colonial Fleet.

[16] The role was not based on a character in the original show and was meant to be confined to the miniseries only -- Helo is shown giving up a spot on a spaceship fleeing the doomed planet of Caprica, with the implication that he was left to die.

In 2009, Penikett was cast as Paul Ballard in Joss Whedon's science-fiction drama television series Dollhouse, which aired on the Fox network Friday nights at 9:00.

[23] In 2014, Penikett guest-starred in the 200th episode of Criminal Minds as Michael Hastings, an ex-CIA agent and leader of the terrorist group, The Regime Squad.