Sean Murray can't get enough of the "renewed energy" the NCIS cast and writers are bringing to season 23, which will extend to episode 500. "I really like the way things are going this year," Murray, who has played Special Agent Timothy McGee since season 1 in 2003, exclusively told Us Weekly on Monday, November 17. "We've got a lot of really interesting, different episodes coming up." The actor, 48, teased that the show's milestone 500th episode will come with a few treats for longtime NCIS fans. "We've got a super cool thing that I can't really talk about at all.