The Blacklist Star You Likely Forgot Played A Character In Mean Girls

Diego Klattenhoff is a relatively lesser-known actor despite a prolific body of work. From an uncredited role in TNT's "Witchblade" adaptation to becoming a recurring character on the hit series "Homeland" (Mike Faber, a role for which he was nominated for a SAG Award), the striking performer has been working steadily for almost two decades. Currently, he appears as a series regular on "The Blacklist," having portrayed FBI Agent Donald Ressler since its first season. 

Ressler is a part of a long-standing tradition of TV cops who need to execute their mission, no matter the personal cost. This same singular mindset arguably cost him his marriage, a healthy relationship with his brother, and even the Reddington case. Despite his sometimes robotic persona, Klattenhoff plays Ressler with a compassionate range that keeps him remain relatable and empathetic to the audience. While this role has been one of his most memorable, he also played a crucial part in the cult classic "Mean Girls."