Stephen Lang is both a film and theatre actor, as well as a playwright!
Lang's first big role was in 1985 in Death of a Salesman. Since then, he has played tons of roles on the screen. This includes a role in Project X, Gettysburg, Tombstone, Tall Tale, The Amazing Panda Adventure, Shadow Conspiracy, Fire Down Below, Trixie, The Treatment, Save Me, From Mexico with Love, Public Enemies, The Men Who Stare at Goats, Avatar, White Irish Drinkers, Conan the Barbarian, and Someday This Pain Will Be Useful to You. He is also already planning to act in 2014's Avatar 2.
You can also see Stephen in Fox's new series, Terra Nova.