Preston is probably best known for his performance as Professor Harold Hill in Meredith Willson's musical "The Music Man" (1962). He had already won a Tony Award for his performance in the original 1957 Broadway production. When Willson adapted his story for the screen, he insisted on Preston's participation over the objections of Jack L. Warner, who had wanted to cast Frank Sinatra or Cary Grant for the role. Preston appeared on the cover of "Time" on July 21, 1958. In 1965, he was the male part of a duo-lead musical, "I Do! I Do!" with Mary Martin, for which he won his second Tony Award. He played the title role in the musical "Ben Franklin in Paris", and originated the role of Henry II in the stage production of "The Lion in Winter", whom Peter O'Toole portrayed in the film version, receiving an Academy Award nomination. In 1974, he starred alongside Bernadette Peters in Jerry Herman's Broadway musical "Mack & Mabel" as Mack Sennett, the famous silent film director. That same year, the film version of "Mame," another famed Jerry Herman musical, was released with Preston starring, alongside Lucille Ball, in the role of Beauregard Burnside. In the film, which was not a box-office success, Preston sang "Loving You", which Herman wrote especially for Preston's film portrayal.