The 30-year-old actor is to play Grant McQueen in the FX drama's seventh and final season, reported Entertainment Weekly.
Smith's character is described as a churchgoer with a dysfunctional family who is forced to make an alliance with the 'Sons of Anarchy'.
Smith joins seventh season guest stars that include rockers Marilyn Manson, Courtney Love and Glee actress Lea Michele.
The Charlie Hunnam-starring 'Sons of Anarchy' is to bow on December 9.
Smith is best known for his portrayal of Max Lewicki in the TNT drama 'Perception'.