Pleasant-looking and genial American character player Reed Diamond delivered a number of early performances prior to his first major assignment -- as Detective Mike Kellerman on the series Homicide: Life on the Street. Diamond carried the role from 1995 through 1998, and reprised it in Jean de Segonzac's 2000 feature Homicide: The Movie. After essaying the Lloyd Bridges role in that same year's telemovie remake of High Noon, Diamond then branched off into cinematic work. He was memorable as John Aaron in George Clooney's Edward R. Murrow biopic Good Night, and Good Luck., and lent supporting roles to the horror picture The Darkroom (2006) and the thriller Adrenaline (2007). Diamond continued to work on the small screen as well, playing Stuart Collins for many episodes of Judging Amy and appearing in episodes of such popular series as CSI, Law & Order, The West Wing, and Ghost Whisperer. In 2007, he scored a regular role on the short-lived sci-fi drama Journeyman, as Jack Vassar, the brother of main character Dan Vasser (Kevin McKidd). He also appeared in the first season of Joss Whedon's short-lived series Dollhouse in 2009, and the next year he landed a recurring part on the 8th season of the FOX action series 24. He returned to the big screen in 2011 playing Mark Shapiro in Moneyball, and returned to the Whedonverse with a role in the director's 2012 adaptation of Shakespeare's Much Ado About Nothing.