Theodore Mann, a Tony Award-winning director and producer who championed Eugene O’Neill and was a driving force behind Circle in the Square Theatre and its school, died Friday in New York of complications from pneumonia. He was 87.“His contributions to Broadway and Off Broadway are immeasurable both in the productions he created and the talent that he nurtured,” said Charlotte St. Martin, the executive director of the Broadway League. “He will be missed by many in our community.” A co-founder of Circle in the Square Theatre in 1951, Mann spearheaded in 1956 the acclaimed revival of O’Neill’s “The Iceman Cometh” and the U.S. premiere of O’Neill’s “Long Day’s Journey Into Night.” Those productions led to a re-evaluation of O’Neill, now recognized as America’s greatest playwright. Mann produced or directed more than 175 plays at Circle, which in 1972 moved from Greenwich Village to its current home on Broadway. In 1963, he founded Circle in the Square Theater School, a program for training young actors. The school’s alumni include Philip Seymour Hoffman, Kevin Bacon, Lady Gaga, Benicio Del Toro, Idina Menzel, Felicity Huffman and Molly Shannon. Mann received the 1957 Tony Award for best play for “Long Day’s Journey Into Night,” a 1976 Special Tony Award acknowledging 25 continuous years of quality productions at Circle in the Square, as well as 12 additional Tony nominations. Together with Paul Libin, Mann presented new and classic works at his theater, including plays by Sam Shepard, Thornton Wilder, Horton Foote, Yazmin Reza, Truman Capote, Arthur Miller, Athol Fugard and Terrence McNally. Some noted Circle productions include “Uncle Vanya,” with George C. Scott; “The Lady From the Sea,” in which Vanessa Redgrave made her Broadway debut; “Salome and Hughie,” with Al Pacino; “The Iceman Cometh,” starring James Earl Jones and directed by Mann; “Candida,” with Joanne Woodward; and “Death of a Salesman,” also with Scott. The Circle has more recently been home to the Broadway premiere of Sam Shepard’s “True West,” the revival of “The Rocky Horror Show,” “Sweeney Todd,” “The 25th Annual Putnam County Spelling Bee,” Alan Ayckbourn’s “The Norman Conquests,” “Lombardi” and the current revival of “Godspell.” Mann also directed operas, including Benjamin Britten’s “Turn of the Screw” for the New York City Opera, “La Boheme” for the Juilliard School and “The Night of the Iguana” for Moscow’s Maly Theater. Mann’s wife, leading lyric coloratura soprano Patricia Brooks, died in 1993. He is survived by two sons and five grandchildren.