It's interesting to watch an actor in a series of shows and try to decide what "business" he does, that he does for that particular character, and what "business" he does because it's his own mannerisms. It's also fun to try to figure out what his real accent is, and what he puts on for any particular character.
I'll be sharing a few of Steve's mannerisms in days to come, but here is, for lack of a better word, "the smirk."
Click on photo to see larger version.
Left - Steve's normal smile. Middle, his smirk. Right, smirk as Keller in Mannix.
I'm actually not sure if it's a smirk, but he does something to his lips that makes it more than a smile!