(Sean Murray).Harmon’s exit as a series regular ends a remarkable run as one of TV’s highest-profile actors on its top-rated drama — though it’s not totally unexpected.In June, “NCIS” added TV veteran Gary Cole and Katrina Law as FBI Special Agent Alden Park and Katrina Law as Special Agent Jessica Knight amidst news that Harmon was cutting back on his on-screen appearances on the series, which premiered in 2003.