Mark is a stuck-up and snooty bully, obsessed with one-upping Edd, Matt, and Tom. However, he is arguably the most one-note of the neighbors, as there isn't much to him other than his shared hostility towards his neighbors. In fact it's implied that pestering Edd and the gang is something he prioritizes. In "Hammer & Fail (Part 2, Rooftop Rumble)", when Edd asks for help in dealing with their possessed house, Mark is visibly disturbed by the menacing, glowing house, before composing himself and brushing it off as looking "stupid as always." Mark has few lines, and when he does, it's either mocking his neighbors, or casual statements that don't imply anything about his personality.

Mark has blond hair combed forward and wears a dark purple turtleneck. Mark also has an exaggerated cleft on his chin.