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.
Filmography
Supernatural
NCIS
CSI: Crime Scene Investigation
Doctor Who
The X-Files
Chuck
Sliders
24
Martial Law
Monk
Star Trek: Voyager
Charmed
Without a Trace
Medium
White Collar
The Practice
Las Vegas
Warehouse 13
Battlestar Galactica
MacGyver
Burn Notice
V.I.P.
Leverage
Doom Patrol
Shark
In Plain Sight
Silk Stalkings
Firefly
Dollhouse
Secret Level