She was also a Nessarose understudy at the time. During the summer of 2004, Espinosa performed as Elphaba for an entire month while Idina Menzel was in South Africa filming the movie "Ask The Dust" with Colin Farrell. During her time as the standby, she went on for both Nessarose and Elphaba. When going on for Elphaba, she performed opposite Kristin Chenoweth and Jennifer Laura Thompson as Glinda. The final time Espinosa ever went on for Elphaba as the standby was on August 22nd, 2004. She departed the Broadway Company on September 5th, 2004 to prepare for the Broadway premiere of Brooklyn The Musical. She was replaced by Shoshana Bean (who later took over from Menzel as the fulltime Principal Elphaba).
While Wicked's First National Tour was in San Francisco from August 5 to September 11, 2005, Espinosa reprised the role of Elphaba temporary filling in for an injured Stephanie J Block. For the San Francisco run, she performed opposite Kendra Kassebaum as Glinda
On January 10, 2006, Espinosa replaced Shoshana Bean as lead Elphaba in the Broadway company. On March 21, 2006, she played the role for Wicked's celebration of its 1,000th performance on Broadway. During her time as the fulltime Principal Elphaba, Espinosa performed opposite Megan Hilty and later Kate Reinders as Glinda. She left the Broadway company on October 8, 2006 was replaced by Ana Gasteyer.
Eden Espinosa was given the 2006 Broadway.com award for "Favorite Female Replacement" for her performances as Elphaba.
On Februrary 21, 2007, Espinosa originated and opened in the Los Angeles production of Wicked as Elphaba performing opposite Broadway co-star Megan Hilty as Glinda. She left the production on December 30, 2007 and was replaced by Caissie Levy. Following appearing as Maureen in the closing company of Rent on Broadway, Espinosa rejoined the Los Angeles company replacing Teal Wicks (once again starring opposite Megan Hilty) on October 31, 2008 and remained with the company till it's final performance on January 11, 2009.
On March 2, 2010, Espinosa once again took over the role of Elphaba from Teal Wicks in the sit-down production in San Francisco (after previously performing there temporary on the First National Tour). She once again performed opposite Tour co-star Kendra Kassebaum as Glinda. Espinosa played her final show on June 26, 2010 and was replaced by Marcie Dodd. The San Francisco Company was Espinosa's final time she ever played Elphaba.
Before her Broadway career, Eden worked in Disneyland as a performer in different shows around the parks. Though she wanted to be Belle, she ended up being cast as Pocahontas and Ariel. Though the reason for her not getting the role of Belle is uncertain, it is said it could have been because she looked too ethnic.