The actor Diego Klattenhoff plays a law enforcement officer on which of the following U.S. TV series?

Diego Klattenhoff (b. 1979), a Canadian actor, is known for his portrayals of Mike Faber in the Showtime series "Homeland" (2011–2020) and as FBI Agent Donald Ressler on NBC's "The Blacklist" (2013–present). Klattenhoff plays the role of FBI special agent (Ressler) who had once been the Acting Assistant Director of the FBI Counterterrorism Division. Prior to his current job as a US government agent, tracking down and apprehending criminals and terrorists, he had been a US Marine Corps captain whose best friend returned to the US after disappearing in Iraq seven years earlier.

Klattenhoff, a popular TV actor, was born in Nova Scotia, Canada. As a kid, he said he wanted to be a professional baseball player. He however at the age of 19 chose to pursue an professional acting career after moving to Toronto. Besides "The Blacklist", he has also appeared in TV shows as Derek in "Whistler" (2007) and Ivan in "Men in Trees" (2008). Additionally, early in his career, he had a minor role in the 2004 film "Mean Girls" as Shane Oman.

Today, Klattenhoff is enjoying his career and in an interview several years ago with "Elle Magazine", he said: "I think life experiences make an actor the best he can be. You are always drawing from your personal life and using your imagination to fill in the blanks when acting."