George M! est un musical de Broadway basé sur la vie de George M. Cohan, la plus grande star de Broadway de son époque qui était connue sous le nom de "L’homme qui possédait Broadway."
Acte I
Jerry and Nellie Cohan waste no time adding their young son to their travelling vaudeville act, "The Four Cohans", with sister Josie. By the time George is 20, they are playing the Columbia Theatre in Cedar Rapids, and George has landed an audition for the family with impresario E. F. Albee. But Albee doesn't make a good enough offer, and George books the act into the Adams Street Theatre in New York. There they meet singer Ethel Levey, and soon George and Ethel get married. Now George is determined to move "The Five Cohans" from vaudeville to musical comedy, and so he writes his first full-length show, The Governor's Son. The musical is a flop, but George is undeterred and opens his next show, Little Johnny Jones. After a momentary crisis of confidence, the company is on stage as George begins the song "Give My Regards to Broadway". By the time the song is over, the Yankee Doodle Kid is a hit.
Acte II
George's career soars higher and higher. He is now a producer, and he and his partner, Sam H. Harris sign Fay Templeton to appear in their show, and we hear some of Cohan's most famous songs, "Mary", "Forty-Five Minutes from Broadway", and "So Long Mary". Ethel feels neglected by her high-flying husband, and the two are divorced. George is crushed, but later meets Agnes Nolan from the cast of Little Johnny Jones. Soon they are married and, together with Agnes, George writes some of his most enduring work, including the songs "Yankee Doodle Dandy", "Harrigan", "Over There", and "You're a Grand Old Flag." But George loses family members, and Broadway is changing – actors are unionizing, and Actors Equity is making demands. George first resists evolving and then retreats from the stage for many years. Eventually, though, Harris offers him a role in I'd Rather Be Right, and, lonely for the stage, he accepts. But his old style is no longer right for 1937, and George is used to being the boss, not just another actor. On stage, alone, George remembers his former glory, singing "Give My Regards to Broadway." He can still tap, after all, and his wife Agnes joins him to reprise "Yankee Doodle Dandy" before he leaves the theatre – at least he's on Broadway.