Steven Blount is an actor in Game of Thrones. He plays the part of Rickard Karstark. Originally Vinnie McCabe has been announced in the role of Rickard Karstark, however he turned out to be playing a Lannister bannerman, Leo Lefford, in the same episode. Blount's CV lists him as playing Lord Karstark.
For the second season it was announced that John Stahl was playing Rickard Karstark. Since Blount's character was never named as Karstark on-screen, it is unclear if he will continue (with the character retrospectively changed to another, miscellaneous Northern lord) or if Stahl is actually replacing him.