Mark plays Jamie's brother "Seth Martin" and first appears in Episode #21 of Season One. He is also in episodes #22 and #24, and then joined the cast for Season Two. He is good friends with Stacey J. Aswad and was recommended by her to Dave Christiano. Mark's main episodes are the two entitled "Jamie's Brother" in Season One, and he also plays a key role in the first two episodes of Season Two.

    

    

Photos - Top row, left to right:
"Jamie's Brother - part 2" (Season One, "22) and "The Other Side" (Season Two, #2)
Bottom row, left to right:
"The Letter - part 4" (Season Two, #12) and "The Ticket" (Season Two, #3)