Hirsh first portrayed Rachel Greene in the eighth season (2001-02) of ER in a storyline where a now teenage and rebellious Rachel leaves her mother in St. Louis to be with her father, Mark Greene; the character returns to St. Louis when Mark dies that season. Hirsh later reprised her role in 2004 in the season 10 episode "Midnight", visiting her stepmother Dr. Elizabeth Corday. In the ER series finale, aired April 2, 2009, titled "And in the End", Hirsh's character returned as a candidate interviewing for medical school, bringing the Greene family history full circle.