The Fourth Symphony is unusual in the weight given to the slow second movement, which is two-and-a-half minutes longer than the last two movements combined. Clearly, Roussel considered this the symphony's heart and soul. In this he was being true to himself; the slow movements are the emotional climax of many of his works — such as the Concert pour petit orchestre, the Sinfonietta, and the Suite in F. etc.).

The pounding rhythms are still there, although muted somewhat in comparison with the powerful Third Symphony. Nonetheless, Breugelesque rhythms break out in all but the slow movement. The symphony is filled with long melodic lines, great excitement and passion.

The Fourth Symphony, though popular in its own right, has been somewhat overshadowed by its more direct and accessible younger sibling. Interestingly enough, Roussel wrote a ballet immediately after both the Third and the Fourth symphonies; and the fate of the two ballets parallels that of the symphonies. Bacchus and Ariane, written after the popular Third, is one of Roussel's most widely acclaimed scores. Aeneas, written after the overshadowed Fourth, is itself even more thoroughly overshadowed — despite containing much music of power and originality.

The Fourth Symphony is the glorious crowning of the composer's remarkable career. It illustrates, in its force, numerous qualities which the French school can take pride in: clarity, spirit, grace and logic. [Alexander Williams]

[The third movement of] No. 4 is a modern, sophisticated version of the kind of movement that Gounod wrote in his 'Funeral March of a Marionette.' [Martin Cooper]

After the controlled rigour of his Opus 42 [Third Symphony], Roussel seems to want to amuse himself like a schoolboy: reducing the Franckist procedure to the extreme; he plays with more freedom and draws form from its own writing process. Its polymodal and polytonal language is even more refined, if that is possible: the ingenious nature of its rhythmic invention supports a tight counterpoint and creates, with a breathtaking impact, a continually renewing palette. [Damien Top]

In this symphony the points of argument are as clearly ordered and defined as any found in a Beethoven symphony. In short, it is a neoclassic composition, straightforward in form, and yet new in its manner of filling each part of the symphonic mold. [Arthur Cohn]

Force, vigor, sanity, act as ballast in a light and translucent edifice of sound. It is hard to tell what draws one most in this work of art — its luminous simplicity, its absence of artifice, its qualities of wit, the certainty of its metier, or the aptness of its thought. [Albert Bernard]