Don S Davis
Actor Don S. Davis made his name playing two military officers on TV; his own military service informed his characterizations. Davis began his career in the 1980s appearing on shows like "MacGyver," where he also worked as a stunt double. His big break came when he was cast on David Lynch's off-kilter mystery show "Twin Peaks" as Major Garland Briggs, an Air Force officer who harbors secrets about the military's UFO investigations. After a wide range of small parts during the rest of the decade he landed his career-defining role on the sci-fi favorite "Stargate SG-1" in 1997, playing the role of Major General George Hammond for 10 seasons before dying of a heart attack in 2008.