30 Rock on NBC is directed by a quite a few different directors.
Here is the full list as found on 30 Rock's IMDB page:
Don Scardino(33 episodes, 2006-2011)Beth McCarthy-Miller(16
episodes, 2007-2011)Gail Mancuso(8 episodes, 2006-2010)Michael
Engler(7 episodes, 2007-2010)John Riggi(7 episodes, 2009-2011)Adam
Bernstein(6 episodes, 2006-2007)Ken Whittingham(3 episodes,
2009-2010)Scott Ellis(2 episodes, 2006-2009)Tricia Brock(2
episodes, 2009-2011)Todd Holland(2 episodes, 2009-2010)Millicent
Shelton(2 episodes, 2009-2010)