The work is written for narrator (voice-type unspecified in the score, but traditionally performed by a soprano) who delivers the poems in the sprechstimme style accompanied by a small instrumental ensemble. Schoenberg had previously used a combination of spoken text with instrumental accompaniment, called "melodrama", in the summer-wind narrative of the Gurre-Lieder, which was a fashionable musical style popular at the end of the nineteenth century. Though the music is atonal, it does not use Schoenberg's twelve-tone technique, which he did not first use until 1921.
Pierrot lunaire is among Schoenberg's most celebrated and frequently performed works. Its instrumentation – flute, clarinet, violin, cello, and piano with standard doublings and in this case with the addition of a vocalist – is an important ensemble in 20th- and 21st-century classical music and is referred to as a Pierrot ensemble.
The piece was premiered at the Berlin Choralion-Saal on October 16, 1912, with Albertine Zehme as the vocalist. A typical performance lasts about 35 to 40 minutes.
The work originated in a commission by Albertine Zehme, a former actress, for a cycle for voice and piano, setting a series of poems by the Belgian writer Albert Giraud. The verses had been first published in 1884 and later translated into German by Otto Erich Hartleben. Zehme had previously performed a 'melodrama' by composer Otto Vrieslander based on the translated poems. But, according to Eduard Steuermann, student of Schoenberg and pianist of the premiere, "the music was not strong enough, and someone advised her to approach Schoenberg..."
Schoenberg began work on March 12 and completed the piece on July 9, 1912, having expanded the forces to an ensemble consisting of flute (doubling on piccolo), clarinet in A (doubling on bass clarinet and clarinet in B♭), violin (doubling on viola), cello, and piano.