Reed Edward Diamond (born July 20, 1967) is an American actor. He is known for the roles of Det. Mike Kellerman on Homicide: Life on the Street, Jason Pillar in season 8 of 24, and recurring character Laurence Dominic on Dollhouse. He also appeared in The Shield, Journeyman, Bones, The Mentalist, Franklin & Bash, and Underground. He had a recurring role on the first two seasons of Designated Survivor as John Foerstel, Director of the FBI, and portrayed Daniel Whitehall / Werner Reinhardt in the Marvel Cinematic Universe (MCU) television series Agents of S.H.I.E.L.D.

Early life and education
Diamond was born in Brooklyn, the son of Allison, an astrologer, and Bob Diamond, a stage manager and director of shows such as The Joe Franklin Show. He was raised in Manhattan and attended the Trinity School.

Diamond attended the University of North Carolina at Chapel Hill for two years, then studied acting at the Juilliard School, where he was a member of the Drama Division's Group 20 (1987–1991).