In the first full-length biography of Joachim, written in 1899 and published in 1901 while Joachim was still alive, Moser praised the musician's ‘great gift of representing different styles’ in his violin playing. Moser continued:

In the following, as we attempt a conclusion, we can apply a similar line of thought to the music of Joachim. He flourished in many styles and genres, and revealed, through his music, skill and familiarity with a breadth of different styles, beginning in a Mendelssohnian idiom and ending by embracing a Prussia-affirming compositional language. We may here briefly assess and summarize his compositional output.

Joachim's early melodic preferences betray Mendelssohn's Lieder ohne Worte in 6/8 metre (combining crotchet, quaver, and dactyl rhythms), while he also inherits his mentor's ‘Elfin character’ (Irish Fantasy) and twomovement, slow-fast pairing (Op. 1). Beside the early Mendelssohnian influence, evidence from the mid-1840s – before Weimar – suggests a clear orientation to the idiomatic solo violin writing of both Charles de Bériot and H. W. Ernst, as revealed in Joachim's now lost Adagio and Rondo (1845) and the two fantasies (1848–52), respectively.

In Weimar (and continuing in Hanover) Joachim transforms himself, under Liszt's important influence, into a composer of serious orchestral programmatic overtures with multi-layered forms, thematic transformation (in the overtures to Hamlet, Demetrius, and Henry IV) and occasionally even acrostics formed with lines from the underlying plays (in said overtures). The Gozzi Overture experiments with a lighter, comic aesthetic; at the same time Joachim does not shake off completely his brooding musical temperament, a sombre passion that remains one of the greatest assets of his compositional style.