[1] Many of his productions broke new ground for musical theater, expanding the possibilities of the form by incorporating more serious and political subjects, such as Nazism (Cabaret), the difficulties of marriage (Company), and the forcible opening of 19th-century Japan (Pacific Overtures).

[5] Prince began work in the theatre as an assistant stage manager to theatrical producer and director George Abbott.

He went on to direct and produce his own productions in 1962 beginning with the unsuccessful A Family Affair[10] followed by his first critically successful musical, She Loves Me (Tony nomination, 1964).

[10][13] He received a Tony nomination for directing On the Twentieth Century (1978) and won twice for the Andrew Lloyd Webber musicals Evita (1980) and The Phantom of the Opera (1988).

It ran for five performances; The New York Times wrote, "It was overproduced and overpopulated to the extent that the tiny resolute figure of Nora became lost in the combined mechanics of Broadway and the Industrial Revolution."

Broadway wags dubbed the show either "A Doll's Death" or, due to the omnipresent portal out of which Nora slammed in the prologue, "A Door's Life."

[26] Prince of Broadway opened in August 2017 at the Samuel J. Friedman Theatre in New York[27][28] with a cast featuring Chuck Cooper, Janet Dacal, Bryonha Marie Parham, Emily Skinner, Brandon Uranowitz, Kaley Ann Voorhees, Michael Xavier, Tony Yazbeck, and Karen Ziemba.

[29] In addition to musicals, Prince also directed operas[13] including Josef Tal's Ashmedai,[30] Carlisle Floyd's Willie Stark, Puccini's Madama Butterfly, and a revival of Bernstein's Candide (Tony Award, 1974).

In 1983 Prince staged Turandot for the Vienna State Opera (conductor: Lorin Maazel; with José Carreras and Éva Marton).

In collaboration with Stephen Sondheim, he was a pioneer in the development of the 'concept musical,' taking its departure from an idea or theme rather than from a traditional story.

"[34] According to The New York Times, "He was known, too, for his collaborations with a murderer's row of creative talents, among them the choreographers Bob Fosse, Jerome Robbins, Michael Bennett and Susan Stroman; the designers Boris Aronson, Eugene Lee, Patricia Zipprodt and Florence Klotz; and the composers Leonard Bernstein, John Kander, Stephen Sondheim and Andrew Lloyd Webber.

[35] A documentary titled Harold Prince: The Director's Life was directed by Lonny Price and broadcast on PBS Great Performances in November 2018.

[36][37] In 2019, The New York Public Library for the Performing Arts presented an extensive exhibit honoring the life and work of Harold Prince.

Hal always looked at the show as this big black box in which the stage craft enabled you to believe there was this impressive scenery all around you.