Many listeners will know Clennon from his role as Miles Drentell on the ABC TV show "thirtysomething." He received and Emmy nomination for the part. Now he plays a drug dealer in the new Paul Schrader film "Light Sleeper" along with Willem Dafoe and Susan Sarandon. He's also been in the films "Missing," "the Right Stuff," "Sweet Dreams," "The Thing," "The Paper Chase," and many others. Offscreen, he's very active in Central American politics.