Tina Fey played which comedy sketch writer in the TV series '30 Rock'?

Tina Fey as Liz Lemon is the protagonist of the series, a "sexually frightened know-it-all" and head writer of TGS with Tracy Jordan.

30 Rock is an American satirical television sitcom created by Tina Fey that ran on NBC from October 11, 2006, to January 31, 2013. The series, loosely based on Fey's experiences as head writer for Saturday Night Live, takes place behind the scenes of a fictional live sketch comedy show depicted as airing on NBC. The series' name refers to 30 Rockefeller Plaza in New York City, the address of the Comcast Building, where the NBC Studios are located and where Saturday Night Live is written, produced, and performed. This series is produced by Broadway Video and Little Stranger, Inc., in association with NBCUniversal.

30 Rock episodes were produced in a single-camera setup (with the exception of the two live episodes that were taped in the multiple-camera setup), and were filmed in New York. The pilot episode premiered on October 11, 2006, and seven seasons followed. The series stars Fey with a supporting cast that includes Alec Baldwin, Tracy Morgan, Jane Krakowski, Jack McBrayer, Scott Adsit, Judah Friedlander, Katrina Bowden, Keith Powell, Lonny Ross, John Lutz, Kevin Brown, Grizz Chapman, Maulik Pancholy, and Rachel Dratch.