In the years before the first World War, young Hungarian composer Sigmund Romberg goes to his job as a musician at New York's Café Vienna, which is owned by the good-hearted Anna Mueller. A slick music promoter, Berrison, comes in and listens to Anna sing one of Sigmund's songs, but dismisses the composer's work as old-fashioned "Viennese oom-pah-pah." Sigmund takes Berrison's challenge and tries his hand at a ragtime number, "Leg of Mutton," which quickly becomes a hit and gains the attention of theater impresario J. J. Shubert. Encouraged by actress Dorothy Donnelly, who is quick to recognize Sigmund's talent, Shubert buys a song for the first act finale of his new Broadway show starring Gaby Deslys. On opening night, Sigmund waits eagerly to hear his composition, but is angry to find that his lovely ballad has been turned into a gaudy production number. Shubert and his associate, Bert Townsend, offer Sigmund a five-year contract but refuse to grant him artistic control over his work. After demonstrating with Anna how his song should have been sung, Sigmund proudly rejects the offer. When Dorothy privately urges him to sign the contract in order to establish a name for himself, however, Sigmund agrees. Sigmund churns out a string of commercial hits for Shubert, and despite his artistic frustration quickly becomes accustomed to material success. After Sigmund repeatedly begs Townsend to consider producing his operetta Maytime , Dorothy comes up with a scheme to get the Shubert organization's attention. Dorothy takes Sigmund to lunch at a fashionable restaurant where Shubert and his associates regularly dine, and leads him to producer Florenz Ziegfeld's table. From across the room, Shubert watches uneasily as Dorothy hands a copy of the operetta to Ziegfeld, who has agreed to go along with their ruse. Although he sees through their game, Shubert finally agrees to produce the show, and Maytime is a huge success, elevating Sigmund to true celebrity status. Determined to maintain artistic control, Sigmund produces his next show himself and loses most of his money. Humbled, Sigmund offers his services to Shubert and Townsend, who warmly welcome him back and assign him to a new project with a short deadline. Sigmund and writers Ben Judson and Harold Butterfield are sent to a mountain lodge to devote themselves exclusively to work. One day, Sigmund has ventured out for a walk when he encounters pretty Lillian Harris and her mother, who mistake the unkempt composer for a tramp and pay him a dollar to fix their flat tire. Later, Sigmund meets Lillian at the lodge, and she is surprised to learn that he is the famous composer. Sigmund quickly falls in love with Lillian, but fails to impress her mother, who considers him vulgar. Lillian at last responds to Sigmund's protestations of love with a kiss, and the following morning he sends her a bunch of violets. However, Townsend has mischievously sent violets "from Sigmund" to every woman at the lodge, and the angry Lillian parts ways with the composer. A year later, Dorothy, who has secretly been in love with Sigmund for years, tells him she has been adapting a German play into a libretto called The Student Prince and would like him to write the score. Sigmund is still morose over Lillian, however, and decides to depart for Europe after the opening of his new show, Artists and Models . Lillian attends opening night with a date, Cumberly, and Anna spots her in the lobby and invites her to a party at the café. Sigmund is stunned when Lillian appears at the party, and again declares his love for her, but she insists that a relationship between them would not work. After Lillian and Cumberly leave, Sigmund, roused from his torpor, declares that he will throw himself into work on The Student Prince . After that operetta's triumphant opening night, Lillian appears before Sigmund in the empty theater and expresses her admiration and love. Sigmund and Lillian are married, and his career continues to flourish. Years later, Dorothy is too ill to attend the opening night of their latest collaboration, My Maryland , and Lillian and Anna spend the evening with her. Sigmund comes in full of plans for their next show, but Dorothy gently says goodbye to her friends, and dies several weeks later. Sigmund is heartbroken at the loss of his partner, but at Lillian's urging, goes to work on a new show with Oscar Hammerstein II, the smash hit New Moon . Sigmund's next few shows fail to catch on, however, and after another unsuccessful opening, Lillian tells her husband she wants to hear him conducting his own music at Carnegie Hall. Sigmund's Carnegie Hall concert, featuring a full symphony orchestra, is a success, and the composer concludes with a loving tribute to his wife.