Jim Caviezel John Reese Actor Michael Emerson Harold Finch Actor Kevin Chapman Lionel Fusco Actor Sarah Shahi Sameen Shaw Actor Amy Acker Root Actor Boris McGiver George Hersh Guest Star Camryn Manheim Control Guest Star John Nolan John Greer Guest Star Leslie Odom Jr. Peter Collier Guest Star John Doman Sen. Ross Garrison Guest Star Joseph Melendez Manuel Rivera Guest Star Julian Ovenden Jeremy Lambert Guest Star Diane Davis Madison Guest Star Ari Butler Vigilance Tech Guest Star Peter Scanavino Adams Guest Star Tom Coiner Decima Tech Guest Star Joel Perez Mask Guest Star J.J. Abrams Executive Producer Bryan Burk Executive Producer Jonathan Nolan Executive Producer David Semel Executive Producer Greg Plageman Executive Producer, Writer David Slack Writer Chris Fisher Director