Caldwell made her Broadway debut in 1965 when she replaced an ailing in . The following year she starred opposite and in ' , an evening of two one-act plays.
The production opened at the Longacre Theatre Feb. 22, 1966, to poor reviews. The New York Times' Stanley Kauffmann wrote: "The sad news from the Longacre is that there really is no news. Mr. Williams has neither grown nor changed."
Despite the negative critical response and the show's brief run of just seven performances, Caldwell was recognized for her work and received the 1966 Tony for Best Featured Actress in a Play.
Caldwell next appeared on Broadway in , 's adaptation of the Muriel Spark novel. She starred as the title character in a cast that included Douglass Watson, Lennox Milne and Roy Cooper.
The play opened Jan. 16, 1968, at the Helen Hayes Theatre, where it ran for 379 performances. Caldwell was lauded for her portrayal of schoolteacher Miss Jean Brodie; New York Times critic Clive Barnes commended her ability to "demand and get the audience's sympathy" and claimed she was "surrounded with an air of ineffable confidence."
Caldwell was awarded the 1968 Tony for Best Actress in a Play, beating out fellow nominees and .
Fourteen years later Caldwell appeared in the title role in a revival of ' Medea, freely adapted by . The cast also starred as the Nurse and Mitchell Ryan as Jason.
Directed by , Medea opened May 2, 1982, at the Cort Theatre. Critic Frank Rich raved about Caldwell's performance in his review for the New York Times. "Euripides demands an intense psychological realism from actors," he wrote, "and that is what Miss Caldwell has bestowed on her marathon role."
She won her third Tony Award, the 1982 Tony for Best Actress in a Play, for her performance.
In 1995 Caldwell took on the role of Maria Callas in the Broadway premiere of 's . The cast also featured as Sharon, as Sophie, as Manny and as Tony.
The production opened Nov. 5, 1995, at the John Golden Theatre and was well received by critics. In his review for the New York Times, Vincent Canby wrote: "For Ms. Caldwell, the role of the preeminent diva of the second half of this century allows her to give what could be one of the funniest, most moving and gaudiest performances of this season and, perhaps, of her career."
Master Class won the Tony for Best Play, and Caldwell took home the award for Best Actress in a Play. and replaced her later in the run.
