Lee Pace's performance in that show is one of my all time favorites. It's incredibly hard to play a charismatic marketing guru because in some sense, you're not acting. In a given scene, the character might be trying to convince people around him of some crazy idea, but if he hasn't convinced you, the viewer, then the entire illusion falls apart. So he really has to do in real life what he's pretending to do on screen.

edit - a great example and one of my favorite scenes from the show: https://www.youtube.com/watch?v=XOR8mk0tLpc