She played on Broadway as Bernadette Peters's replacement in the role of "Dot" in Sunday in the Park with George in 1985. In 1987, she won the Tony Award for Best Leading Actress in a Musical for her performance as "Sally Smith" in Me and My Girl.
She and Jay O. Sanders were married in 1991. They met while acting on the television series A Man Called Hawk.
She performed in the National Actors Theatre productions of A Little Hotel on the Side by Georges Feydeau and Maurice Desvallières on Broadway in 1992, and in The Seagull by Anton Chekov in 1992.
She and her husband Jay O. Sanders appeared together in the Richard Nelson play Sorry in 2012 at the Off-Broadway Public Theatre.
Plunkett and Sanders appeared in Sweet and Sad in September 2011 at the Public Theatre. Sweet and Sad won the 2012 Drama Desk Award, Outstanding Ensemble Performance and the 2012 Obie Award, Ensemble Performance. She appeared in The Apple Family Plays in repertory at the Public Theatre, from October 22, 2013 to December 15.
Plunkett and Sanders appear in all three of Nelson's new play cycle, with the overall title of The Gabriels: Election Year in the Life of One Family. The first play, Hungry, premiered in March 2016 at the Public Theatre. The second play, What Did You Expect? ran at the Public Theatre from September 10, 2016 to October 9. The third and final play, Women of a Certain Age, opened on election night, November 8, 2016 and runs to December 4, at the Public Theatre.
