Who plays Professor James Gellar in Dexter season 6?

Edward James Olmos plays Professor James Gellar in Dexter season 6.

Gellar is introduced as a former religious studies professor whose writings and interpretations of the Book of Revelation influence a series of apocalyptic murders. His name becomes central to the season’s investigation as Dexter and the Miami Metro team try to understand the symbolic pattern behind the killings.

Olmos appears in a special guest role alongside Colin Hanks, whose character Travis Marshall is drawn into the murder scheme. The season uses Gellar’s academic background to connect theology, symbolism, and criminal investigation rather than presenting him as a conventional police or forensic specialist.

A frequent mix-up comes from the show’s large roster of notable guest actors. Jimmy Smits appears in Dexter as Miguel Prado, Ray Stevenson plays Isaak Sirko in season 7, and John Lithgow portrays Arthur Mitchell in season 4. None of those actors plays Professor Gellar.