On The Blacklist, FBI Special Agent Donald Ressler has been tracking Raymond “Red” Reddington (James Spader) for years. He’s been willing to give up his life (or at least his love life) in order to catch Red. When Red turned himself in, Ressler had his doubts about Red’s motives and why he wanted FBI agent Keen (Megan Boone) assigned to his case. In Season 3, Ressler’s obsession shifts to Keen. It’s his mission to stop her from getting on a plane to Moscow where she seeks asylum.
Ressler is portrayed by Diego Klattenhoff. He’s best known for his role as Mike Faber in Homeland. The Canadian-born (Nova Scotia) actor also had a recurring role on Mercy with Taylor Schilling (Mike Callahan), 24 with Keifer Sutherland (Sergeant Cadden), and Men in Trees with Anne Heche (Ivan Palacinke). The Blacklist airs Thursdays at 9pm on NBC.