The narrator (voice-type unspecified in the score, but traditionally performed by a soprano) delivers the poems in the Sprechstimme style. 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. The melodrama is in atonal form, yet does not use Schoenberg's twelve-tone technique.
The composition is among Schoenberg's most celebrated and frequently performed works. The instrumentation of the piece, flute, clarinet, violin, cello, and piano (with standard doublings and in this case with the addition of a vocalist), has subsequently been named after Schoenberg's composition and is now referred to as a Pierrot ensemble.
The work originated in a commission by Zehme 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. Schoenberg began on March 12 and completed the work on July 9, 1912, having expanded the forces to an ensemble consisting of flute (doubling on a piccolo), clarinet (doubling on bass clarinet), violin (doubling on viola), cello, and piano. After forty rehearsals, Schoenberg and Zehme (in Columbine dress) gave the premiere at the Berlin Choralion-Saal on October 16, 1912. Reaction was mixed. According to Anton Webern, some in the audience were whistling and laughing, but in the end "it was an unqualified success". There was some criticism of blasphemy in the texts, to which Schoenberg responded, "If they were musical, not a single one would give a damn about the words. Instead, they would go away whistling the tunes". The show took to the road throughout Germany and Austria later in 1912. It was performed for the first time in America at the Klaw Theatre in New York City on February 4, 1923, with George Gershwin and Carl Ruggles in attendance.
"Pierrot Lunaire" consists of three groups of seven poems. In the first group, Pierrot sings of love, sex and religion; in the second, of violence, crime, and blasphemy; and in the third of his return home to Bergamo, with his past haunting him.
Schoenberg, who was fascinated by numerology, also makes great use of seven-note motifs throughout the work, while the ensemble (with conductor) comprises seven people. The piece is his opus 21, contains 21 poems, and was begun on March 12, 1912. Other key numbers in the work are three and 13: each poem consists of 13 lines (two four-line verses followed by a five-line verse), while the first line of each poem occurs three times (being repeated as lines seven and 13).