For producer David Merrick, who initially presented the play on Broadway, "I Do! I Do!" was an ideal investment in that it had neither expensive sets and costumes nor a large cast. After four previews, the Broadway production, directed and choreographed by Gower Champion, opened on December 5, 1966 at the 46th Street Theatre and closed on June 15, 1968 after 560 performances. Mary Martin and Robert Preston comprised the original cast. Carol Lawrence and Gordon MacRae played matinees starting in October 1967 and then replaced Martin and Preston in December 1967.