Elementary is a television series.
Aidan Quinn . He currently plays Captain Thomas `` Tommy '' Gregson in the CBS television series Elementary . Elementary (TV series) . His indifference to police procedure often leads to conflict with Captain Thomas Gregson ( Aidan Quinn ) , although the two still remain mutually respectful of one another . Robert Doherty is the creator , executive producer and writer of the American television mystery series Elementary , starring Jonny Lee Miller , Lucy Liu and Aidan Quinn .