Bruce Mars played Finnegan, the swaggering Academy upperclassman who tormented the young Kirk and reappears on the amusement-park planet in Shore Leave, and a policeman in Assignment: Earth.
Bruce Mars is remembered by Star Trek viewers chiefly for one role. In Shore Leave he is Finnegan, the practical joker who made Kirk's first year at Starfleet Academy miserable. When Kirk thinks of him on the shore leave planet, a copy appears, laughing and spoiling for the fist fight that Kirk has wanted for years; the long brawl across the rocks is one of the episode's set pieces.
Mars returned at the end of the second season in Assignment: Earth as Charlie, one of two New York policemen who are accidentally beamed aboard the Enterprise and promptly sent back.
He left acting in the 1970s after a short career in film and television.