Although the work was only seriously outlined by 1819, the famous first theme of the allegro ed appassionato was found in a draft book dating from 1801 to 1802, contemporary to his Second Symphony.

The first movement, like many other works by Beethoven in C minor, is stormy and impassioned—the tempo markings may be translated, respectively, as "majestic" and "brisk, with vigor and passion".

It abounds in diminished seventh chords, as in for instance the first full bar of its opening introduction, which may have provided the inspiration for the introduction of Chopin's Second Piano Sonata:[7] Unlike Beethoven's other C minor sonata-form movements, the exposition of this movement moves to the submediant (A♭ major), not to the mediant, as its second key area.

Overall, the first movement contains motivic similarities with Mozart's Adagio and Fugue in C minor, which Beethoven arranged for a string quartet (Hess 37).

This moment is also prepared by the inclusion of the minor-mode inflected flattened sixth (F♭) at the corresponding point in the exposition's closing theme.

4 and 5) are famous for introducing small notes which constantly divide the bar into 27 beats, which is very uncommon.

Beethoven's markings indicate that he wished variations 2–4 to be played to the same basic (ternary) pulse as the theme, first variation and subsequent sections (that is, each of the three intra-bar groupings move at the same speed regardless of time signature; Beethoven uses the direction "L'istesso tempo" at each change of time signature).

The third variation has a powerful, stomping, dance-like character with falling swung sixty-fourth notes, and heavy syncopation.

Mitsuko Uchida has remarked that this variation, to a modern ear, has a striking resemblance to cheerful boogie-woogie,[9] and the closeness of it to jazz and ragtime, which were still over 70 years into the future at the time, has often been pointed out by, among others, Igor Stravinsky.

[12] From the fourth variation onwards the time signature returns to the original 916 but divided into constant triplet thirty-second notes, effectively creating a doubly compound meter (equivalent to 2732).

The work is one of the most famous compositions of the composer's "late period" and is widely performed and recorded.

The pianist Robert Taub has called it "a work of unmatched drama and transcendence ... the triumph of order over chaos, of optimism over anguish.

"[13] John Lill sees Beethoven's struggle that permeates the first movement as physically challenging pianists performing this work; even in the opening of the sonata, for instance, there is a downward leap of a seventh in the left hand – Beethoven is making his pianists physically struggle to reach the notes.

In 2009, the Italian composer Lorenzo Ferrero wrote a composition for piano solo entitled Op.

111 – Bagatella su Beethoven, which is a blend of themes from this sonata and Dmitri Shostakovich's musical monogram DSCH.