He has since received much praise for his contribution to the role.He also voiced Darth Sidious (Emperor Palpatine) in both games, and reprised it for the games Disney Infinity 3.0 and Battlefront and for season 2 of Star Wars Rebels, For Star Wars: The Clone Wars, Witwer had also vocally performed the Son in a three episode story arc (known as the Mortis trilogy) in Season 3 as well as the iconic Sith Lord Darth Maul in the Season 4 finale episodes and in four episodes of Season 5.
Witwer's first on-screen credit was for a Chicago Bulls commercial. Crashdown in science fiction show Battlestar Galactica. From 2008 to 2009, Witwer had been cast as Davis Bloome for the eighth season of Smallville.
His character was a charming paramedic that doubles as the show's incarnation of Doomsday.
Witwer's performance in Smallville was incredibly well-received, and he has stated that his experience on the show had opened more opportunities for him in the future of acting.
Witwer made a cameo appearance in The Walking Dead as a dead (zombie) soldier in a tank in the Season 1 episode "Days Gone Bye" which reunited him with director Frank Darabont from The Mist.
Sam is an avid player of both electronic games and pen-and-paper roleplaying games. He has been a frequent guest on the Podcast Order 66 and has expressed a love for all iterations of Star Wars roleplaying games Star Wars: The Roleplaying Game (by West End Games) to Star Wars Roleplaying Game (by Wizards of the Coast) and to the current series of cross-compatible Star Wars roleplaying games by Fantasy Flight Games.
A lifelong Star Wars fan, Witwer provided both his voice and likeness for lead character Galen Marek/Starkiller (Darth Vader's secret apprentice) in the 2008 video game Star Wars: The Force Unleashed and 2010 sequel Star Wars: The Force Unleashed II.
During Celebration VI, he also had his own panel called Sam Witwer "The Maul Within" on August 26, 2012.
In 2013, he attended for the first time the annual event, Star Wars Weekends at Disney's Hollywood Studios in Orlando, Florida for a three-day weekend and fans praised him for his roles in The Force Unleashed games and on The Clone Wars.
He also lent his voice for Darth Maul in other projects such as the Star Wars: Episode I Brisk commercial as well as the Cartoon Network special Lego Star Wars: The Empire Strikes Out, and is playing Maul again for Star Wars Rebels.
Sam attended The Clone Wars Season 5 Red Carpet Premier in Orlando, Florida on August 24, 2012 during Celebration VI along with some of his co-stars Matt Lanter, James Arnold Taylor, Dee Bradley Baker, Tom Kane, Daniel Logan, Stephen Stanton and Ashley Eckstein, as well as Supervising Director Dave Filoni.
He also voiced protagonist Galen Marek/Starkiller in the multimedia project Star Wars: The Force Unleashed, as well as The Son and Darth Maul in Cartoon Network's Star Wars: The Clone Wars and Emperor Palpatine as well as Maul in Disney XD's Star Wars Rebels.