Marquette has also been seen as a guest star on several TV shows, such as ER, Touched by an Angel, 7th Heaven, Miracles, Boston Public and Judging Amy. The latest guest roles include the Showtime TV series Huff; Christopher played James, a friend of Byrd's (Anton Yelchin, whom he also played alongside in Alpha Dog), in episodes Sweet Release, Bethless and Tapping The Squid (all aired 2006). As Christopher Marquette, he returned on-screen, in late 2010, with fellow Joan of Arcadia actor Michael Welch as two friends who murder together in the Criminal Minds' episode entitled "JJ". In 2011 he appeared as Danny, a young homeless patient who is later revealed to be a cannibalistic serial killer in the award-winning medical drama House.