The Sinfonietta is in three movements. It is scored for a full-sized orchestra without strings.

The first movement is mostly of rhythmical character with some impressionistic colouring. The exposition introduces alternately themes of a lyrical and playful nature (themes (a) and (c)), and themes of a more rhythmical nature (themes (b) and (d)). The themes also alternate in colour between the woodwinds and the brass.  The middle section is dominated by the brass instruments with theme (e), and in the dynamic climax of this section, the full orchestra is employed. The final section brings back the themes of the exposition but completely re-orchestrated with a different texture. The movement ends pianissimo. As if from a distance, we hear theme (a) one last time.

The second movement, subtitled "Elegy", was composed during the last months of the life of the composer's father, and it is dedicated to his memory. It is ternary both in orchestration and thematic material. The first part, a dirge-like slow march, employs only brass and drums. The middle section, an expressive Andante, is scored almost exclusively for woodwinds, with muted brass joining for only four bars. Later in its dynamic climax, the full orchestra joins in combination with the high-pitched percussion of the xylophone, glockenspiel, vibraphone and the whip. The last section is again scored for brass only, with several of the "deep" percussion like bells and tam-tam added to the drums, giving a specially gloomy colour to the very low E-flat of the tuba and bass trombone, the last note of the movement.

The third movement, with its continuous motion, could almost be described as a Toccata. The motion hardly stops, but the mood changes frequently. After the stormy beginning, a playful theme is played by the oboe and piccolo, and other short motifs with superimposed trills are in the background. The movement ends with a steady rising crescendo, based on the four opening themes.