Mark Sheppard

Mark Andreas Sheppard (born 30 May 1964) is a British actor and musician. He is often credited as Mark A. Sheppard. Sheppard is known for playing the demon/King of Hell Crowley on Supernatural and for his recurring roles as lawyer Romo Lampkin on the Battlestar Galactica reboot, Interpol investigator James Sterling on Leverage, and small-time crime lord Badger on Joss Whedon's Firefly.
Description above from the Wikipedia article Mark Sheppard, licensed under CC-BY-SA, full list of contributors on Wikipedia.