The voice acting of the series is relatively low - key, and the intention was to make most of the characters sound natural and conversational. Quintel wanted to make the show listenable and given contrast to most other cartoons, which often are difficult for adults to listen to. The main cast consists of voice acting veterans Mark Hamill, who portrays Skips and Roger Craig Smith, who plays Thomas. William Salyers plays the voice of Rigby, Janie Haddad portrays Margaret and Quintel 's former CalArts classmate Sam Marin voices Benson, Pops, and Muscle Man. Quintel portrays Mordecai and Hi - Five Ghost. Members of the production staff have voiced several characters throughout the series; these include Minty Lewis, Toby Jones, Andress Salaff, and Matt Price. The Regular Show cast record their lines together in group as opposed to individual recording sessions for each actor; this is to help the show 's dialogue sound natural. The series regularly uses guest voice actors for recurring characters; these guests include Steven Blum, Courtenay Taylor, David Ogden Stiers, Robin Atkin Downes, Jeff Bennett, Jennifer Hale, David Kaye, Fred Tatasciore and Julian Holloway.
who does mark hamill voice in regular show
Skips