Clark's stage work includes roles in the Broadway musicals Guys and Dolls (1992–93), A Grand Night for Singing (1993–94), How to Succeed in Business Without Really Trying (1995–96, as Smitty), Titanic (1997–99, creating the role of Alice Beane), Cabaret (1999–2000, as Fraulein Kost) and Urinetown (2003, as Penelope Pennywise), as well as numerous roles Off-Broadway, in national tours and in regional theatre. She played Doris MacAfee in the City Center Encores! production of Bye, Bye Birdie in 2004.