He also plays Aidan Waite on the SyFy channel series Being Human.
Witwer was the fifth Battlestar Galactica alum to have a role on Smallville: he played Alex "Crashdown" Quartararo on the series. The Battlestar Galactica actors that came before him Rekha Sharma, Aaron Douglas, Tahmoh Penikett, Donnelly Rhodes, Ty Olsson and Alessandro Juliani.
Witwer grew up in Glenview, Illinois, outside of Chicago. He attended Glenbrook South High School, during which time he was involved in drama and theater classes, as well as being the lead singer of a high school band. He attended the Juilliard School of Drama.
- His astrology sign is Libra
- 6' 1" (1.85 m)
- Attended the Juilliard School of Drama
Witwer has appeared as a soldier Jessup in The Mist, as Crashdown on Battlestar Galactica and released a CD titled Colorful of the Stereo.
It was announced in June 2008 that Witwer had been cast as Davis Bloome (aka Doomsday, the character from the Superman comics that was best known for being the only villain to have killed Superman), a charming paramedic, on Smallville. He appeared in 12 episodes in Season Eight.
In September, 2008 Witwer appeared as Darth Vader's secret apprentice,Galen Marek in the multimedia Star Wars project The Force Unleashed, providing both his voice and likeness to the character across all of the media.
In 2010, he again appeared as Marek in the multimedia Star Wars project The Force Unleashed 2, providing both his voice and likeness to the character across all of the media.
Witwer starred alongside Sam Huntington, who previously portrayed Jimmy Olsen in 2006's Superman: Returns in the American remake of BBC's supernatural drama series Being Human on the SyFy Channel in the US and Space in Canada.
Witwer also returned to the Star Wars universe by voicing the Celestial known as the Son in the Mortis trilogy in the Star Wars: Clone Wars series on Cartoon Network, a character with strong ties to an essential antagonist from the Star Wars Legends continuity.
In 2012, Witwer returns to Star Wars: Clone Wars series in a three-part mini saga voicing the iconic character from Star Wars, Episode I: The Phantom Menace - Darth Maul.
Justice League: Throne of Atlantis - Ocean Master