Arnold Moss. It's hard to believe from Conscience of the King that he taught acting. I have friend who had Moss as an acting teacher. That friend later went on to become... a lawyer.
Moss was a brilliant actor, and I find his performance on Trek to be no exception. What rings false to you?
On a side note, I often wish my fellow trial lawyers had had some theatrical training. Most could use it. Funnily enough, whenever I'm in front of a jury, I try to channel Kirk-era Shatner.