Like Bernstein's West Side Story and many of his other works, Divertimento is made up of an exuberant array of styles, from various types of American popular music to symphonic repertoire from different historical periods. In this instance these references work as a series of reminiscences and tributes, relating to the piece's composition for the centenary of the Boston Symphony Orchestra. On the eve of its premiere, Bernstein, a Boston native, the Boston Globe that, "It reflects my youthful experiences here where I heard my first orchestral music, I nearly fell out of my chair I was so excited."
For the most part the work is lighthearted, and the composer's sense of fun is typified by his instruction that the piccolo, and later the brass section, stand up for their solos in the finale, as if they were playing in a brass band concert. This rousing conclusion to the work, "The BSO [Boston Symphony Orchestra] Forever" is a pastiche of a march, the "Radetzky", which was played regularly at the Boston Pops concerts which Bernstein attended. It follows directly on from the more somber "In Memoriam," where the composer remembers Boston players and conductors who have passed away, with a short passage for three flutes where the instruments play the same melodies at staggered intervals of time (a canon).
Like the march, the "Samba" and "Turkey Trot" movements are in the style and mood of the Pops concerts, and the "Blues" movement draws on the popular music style which Bernstein had heard when visiting Boston nightclubs in his youth. The "Mazurka" and "Waltz," on the other hand, refer to Beethoven and Tchaikovsky, respectively; the "Mazurka" incorporates a quotation of the oboe cadenza of the first movement of Beethoven's Fifth Symphony, while the "Waltz"--often singled out as a particularly engaging part of this piece--is in the irregular time of 7/8, and is an homage to Tchaikovsky, particularly the 5/4 waltz of his Sixth Symphony. The opening movement, "Sennets and Tuckets," begins with celebratory fanfares, and its title is derived from a Shakespearian stage direction for that type of flourish (Bernstein had originally planned to use the first movement material as the basis for the whole work, but this scheme gave way in the face of the huge range of ideas which later occurred to him).
The melodic basis for the entire work is the two-note "germ" B-C, (representing "Boston Centenary"). The piece is shaped by the use of a range of different combinations of soloists and small groups for the separate movements, with, for example, the "Waltz" for strings alone; the "Blues" using brass and percussion; and woodwind and harp coloring the "Mazurka" movement.