Her other theater credits include Craig Lucas' 2007 play Prayer for my Enemy at the Long Wharf Theatre in New Haven, Connecticut, and the Deborah Abramson/William Finn musical revue Travels With My Discontent at the Barrington Stage Company.

[5] She succeeded Christina DeCicco on November 6, 2007, and starred alongside Carmen Cusack as Elphaba, who was later replaced by her standby Donna Vivino.

[11] She returned to the role of Glinda in the Broadway production of Wicked from April 23, 2013, to September 22, 2013, where she starred alongside Willemijn Verkaik and later Lindsay Mendez.

[12] In November 2013, Clarke made her cabaret debut at 54 Below, where she performed a mix of acoustic pop, folk, country, and original songs.

[15] In May 2014, Clarke returned to the Long Wharf Theatre to star as Cathy Hyatt in Jason Robert Brown's two person musical, The Last Five Years.

[18] Clarke once again returned to the role of Glinda in the Broadway production of Wicked beginning December 11, 2018, replacing Amanda Jane Cooper.

[21] Beginning in September 2023, Clarke starred as Beth Shepard in the first Broadway revival of Merrily We Roll Along after playing the role at the New York Theatre Workshop in 2022.