Diego Klattenhoff (born November 30, 1979) is a Canadian actor known for his portrayals of Mike Faber in the Showtime series Homeland and as FBI Special Agent Donald Ressler in The Blacklist.

[citation needed] Klattenhoff studied with some of Canada's most respected acting coaches, including David Rotenberg (author), Bruce Clayton and Rae Ellen Bodie.

Since 2006, he has been in recurring roles like Young Jacob in CBC Television's At the Hotel, Derek in CTV's Whistler, Ivan Palacinke in ABC's Men in Trees and Mike Callahan in NBC's Mercy.

Klattenhoff appeared in Homeland as Mike Faber, a Marine Captain whose best friend returns to the U.S. after disappearing in Iraq eight years earlier.

[7] In March 2013, Klattenhoff joined the cast of the NBC thriller The Blacklist, as FBI Special Agent Donald Ressler.