Jim Rash, who portrays Dean Pelton, was promoted to a series regular after having a recurring role throughout the first two seasons. Michael K. Williams was cast as the study group's new biology professor, who is described as a deeply intense character. John Goodman appears in a multi-episode arc as Vice Dean Laybourne, the head of Greendale's air conditioning repair school, and is a foe for Dean Pelton. 21 Episodes include Biology 101, Geography of Global Conflict, Competitive Ecology, Remedial Chaos Theory, Horror Fiction in Seven Spooky Steps, Advanced Gay, Studies in Modern Movement, Documentary Filmmaking: Redux; more.
Donald Glover,Danny Pudi,Alison Brie,Yvette Nicole Brown,Gillian Jacobs,Joel McHale