Warfield examines Sousa's wide-ranging experience composing, conducting, and performing in the theater, opera house, concert hall, and salons, as well as his leadership of the United States Marine Band and the later Sousa Band, early twentieth-century America's most famous and successful ensemble. Sousa composed not only marches during this period but also parlor, minstrel, and art songs; parade, concert, and medley marches; schottisches, waltzes, and polkas; and incidental music, operettas, and descriptive pieces. Warfield's examination of Sousa's output reveals a versatile composer much broader in stylistic range than the bandmaster extraordinaire remembered as the March King.

In particular, Making the March King demonstrates how Sousa used his theatrical training to create the character of the March King. The exuberant bandmaster who pleased audiences was both a skilled and charismatic conductor and a theatrical character whose past and very identity suggested drama, spectacle, and excitement. Sousa's success was also the result of perseverance and lessons learned from older colleagues on how to court, win, and keep an audience. Warfield presents the story of Sousa as a self-made business success, a gifted performer and composer who deftly capitalized on his talents to create one of the most entertaining, enduring figures in American music.