In 2003, Parker joined the Season 9 cast of Mad TV. She was a featured performer, until Season 10, when she was promoted to cast member. Parker left the show in November 2008, but appeared in sketches until the series finale in 2009.
In 2004, Parker was nominated for a Jeff Award for her performance in The People vs. Friar Laurence, The Man Who Killed Romeo and Juliet.
From July 2006 to January 2007, Parker performed in the comedy musical Martin Short: Fame Becomes Me.
In 2009, Parker replaced Marcie Dodd in the role of Elphaba in the Broadway production of the musical Wicked, from January 16. She starred opposite Alli Mauzey as Glinda. She exited on July 19 at the end of her six-month contract, and was replaced by Dee Roscioli.
Parker recently starred in the new musical The People in the Picture, which began performances at Studio 54 on April 1, 2011 and officially opened on April 28, 2011.
