The monumental nature of much of the orchestral work of Brahms is in part a sign of the great pains that went into its construction. His first piano concerto, which made no concessions to contemporary taste, was, it seems, conceived originally as a sonata for two pianos. This then became a symphony, to reach its final metamorphosis as the Piano Concerto in D minor, Op. 15, completed in this form in 1859. The original conception in 1854, came at the time of Schumann's illness and was developed during the difficult final years of the latter's life, suggesting, particularly in its slow movement a Requiem for Schumann.

The concerto had its first private rehearsals, with Brahms as soloist, in Hanover in 1858, with Joachim conducting. They introduced the work to the public in January the following year to a polite reception. This relative success persuaded Brahms to the more ambitious step of a performance in Leipzig with the Gewandhaus Orchestra, conducted by Julius Rietz, once Mendelsson's assistant in Düsseldorf and now established in Leipzig in succession to Niels W. Gade.The reaction of the audience to such a demanding work was hostile, with ironic applause from one or two and hissing from many. A well known critic found nothing good to say about the concerto and even less to commend in Brahms's performance as a pianist, at the time his principal means of earning a living. His later supporter Hanslick, indeed, writing three years later, found that Brahms played more like a composer than a virtuoso, praising his honesty, his interpretative abilities, yet aware of inaccuracies however compelling the whole performance. A subsequent performance of the concerto in Hamburg met a better reception. In the following years the work gradually won wider acceptance, finding its way early into the repertoire of Clara Schumann, a strong advocate. The concerto is massive in its symphonic conception, described by one contemporary as a symphony with piano obbligato, and clearly posed problems to its first audiences, lacking any trivial or superficial brilliance in its writing and calling for sustained attention over its very considerable length. As the symphonies Brahms was to write might seem an extension of the work of Beethoven half a century earlier, so the first of his two piano concertos seemed to continue and develop the pattern set by Beethoven's Emperor Concerto. In November 1855 Brahms had appeared as a soloist with orchestra for the first time in a performance of that concerto and included Beethoven's Fourth Concerto and Mozart's D minor and C minor Concerto, in his concert repertoire at this time. These all had an observable influence on his own writing.

The first movement opens with a feeling of tragic significance, the marked trills adding to its ominous nature, before a gentler element, a foretaste of the second subject, intervenes, followed by a sudden outburst from the orchestra, which returns to its opening mood, hushed only by the entry of the soloist. The pianist succumbs, in turn, to the initial theme with its fierce trills, leading to the second subject, a hymn-like theme announced by the soloist. The material is developed in a section that makes heavy demands on the solo instrument and the recapitulation brings its own surprising shifts of key. The massive first movement is followed by a contrasting slow movement. Over the melody of the Adagio Brahms wrote the words Benedictus qui venit in nomine Domini (Blessed is he who comes in the name of the Lord), a reference, it is supposed, to his master, Schumann, although he is also said to have identified the movement with Clara Schumann.The liturgical reference was later crossed out, in an attempt, to conceal, perhaps, such an overt display of feeling. A long-drawn theme is played by the strings, the bassoon joining the bass, with the piano adding its own meditation on the melody. As in the first movement, the horns have a characteristically evocative part to play, however brief, while the piano continues its progress towards a new theme. The mood of the opening returns, extended in a cadenza of great serenity. The last movement, a Rondo, has a marked and energetic opening that may remind one of Beethoven, both in his Concerto in C minor and in other final movements, including, even, in some of the keyboard writing, that of the first piano sonata. The rondo form allows the inclusion of a number of contrasting ideas, an F major episode introduced by the piano and developed by the orchestra and a later episode introduced by the violins, but treated contrapuntally, as is the principal theme, before it has gone too far into a purely lyrical mood. A cadenza, marked quasi fantasia and using a dominant pedal-point, a sustained note to underpin changes of harmony, a feature characteristic of Brahms, leads to a moving conclusion.