Elizabeth "Liz" Lemon is the fictional protagonist of the American situation comedy 30 Rock. She is portrayed by Tina Fey, who is also the creator of the series and its show runner.
Like Fey, who was head writer of Saturday Night Live (SNL) from 1999 to 2006, the character is head writer for a fictional SNL-esque show, The Girlie Show.
For this reason, Liz Lemon is widely seen by critics as a fictionalized version of Fey herself, which Fey herself has confirmed as being her intention.
Tracy: But I promised Barbara Streisand I'd never stab her again.