In December 2008, Wiethoff was travelling home when he received a call from his agent, telling him that he had an audition for an "untitled video game project". He completed the audition feeling discouraged that he was not going to be given the role. However, a few days later, he received news that he had won the role, and shooting began in January 2009. The project was ultimately titled Red Dead Redemption, developed by Rockstar San Diego and published by Rockstar Games. For the game, Wiethoff provided the voice and motion capture for the main playable protagonist John Marston, a former outlaw. Most of the game's story takes place in 1911, during the twilight of the American frontier.
In August 2013, it was announced that Wiethoff would be the voice of Lazarus in the interactive radio drama Codename Cygnus, developed by Reactive Studios. The episode featuring Wiethoff was released in September 2013.
