17John Noble - Denethor
As one of the most well-known actors on this list of secondary characters, John Noble played Denethor. Denethor lost all hope in The Lord of the Rings movies, thinking that Sauron couldn't be defeated. He made terrible decisions, and, in a memorable scene, refused to have the beacons lighted
to get help to Rohan.
Noble has an extensive career going back to 1988. He's still a busy actor, sometimes maintaining multiple roles in television shows and movies at the same time. He voiced Dr. Jonathan Crane/The Scarecrow in the video game Batman: Arkham Knight, starred in sci-fi series Fringe, and played Morland Holmes for a season on Elementary on CBS. You might especially remember him as Henry Parrish in Sleepy Hollow, which won't have a season five.
Currently, he is Nicholas Tanz in the TV show Salvation. He will appear in two movies that have just been announced: Stream and Guardians of Luna. He's also the spokesperson for his charity, Noble Bones, which is meant to raise awareness for osteoporosis.