Arnold Schoenberg was born in Vienna on September 13, 1874, to Jewish parents. He began learning the violin at the age of eight and simultaneously started composing self-taught, leaving behind pieces that imitated familiar violin works from his childhood. After his father's death in 1890, while working at a private bank, he received education in harmony and music theory from Oskar Adler, and also briefly studied composition under Alexander Zemlinsky. Around this time, Schoenberg also began learning the cello, though his skill was reportedly far from that of a professional musician.

After leaving the bank in 1895, Schoenberg first embarked on his musical career as a choral conductor. The choirs he conducted at the time included the male choir “Beethoven” in Heiligenstadt, and these conducting activities continued until he moved to Berlin at the end of 1901. In 1898, Schoenberg began his career as a music teacher, a profession he would pursue throughout his life. Notably, Schoenberg's compositional interests shifted significantly from string-centric works in the early 1890s, leading to the composition of many songs with piano accompaniment during this period. In addition to songs, a small number of piano pieces, choral works, and orchestral pieces were composed, though many remained unfinished.

The string sextet Verklärte Nacht (Transfigured Night), Op. 4, composed in 1899 and based on Richard Dehmel's poem of the same name, is considered one of Schoenberg's important early works. It features not only innovative sounds created by chromaticism but also formal ambiguity, combining sonata form with the formal implications of Dehmel's poem. The following year, in 1901, he began composing the orchestral song cycle Gurrelieder. This work was initially conceived for a composition competition organized by the Gesellschaft der Musikfreunde in Vienna, but its orchestration was not completed until 1911. Moving to Berlin at the end of that year, Schoenberg became acquainted with Richard Strauss there. Strauss's appreciation of his symphonic poem Pelleas und Melisande led Schoenberg to secure a position as a music lecturer at a university and receive a grant. During his stay in Berlin, he also made contact with Max Marschalk, who founded the publishing house Dreililien Verlag, which published Schoenberg's relatively small-scale works. After returning to Vienna in the summer of 1903, he befriended Gustav Mahler, who was then the music director of the Vienna Court Opera. In 1904, he took Alban Berg and Anton Webern as his pupils. The early works written by this time still show a strong influence of late Romanticism, particularly from Wagner and Mahler. Around the same time, he also began arranging works by other composers.

With the completion of String Quartet No. 2, Op. 10, in 1908, Schoenberg is said to have completely abandoned tonal composition, reaching atonality. The genre-mixing instrumentation of Op. 10, combining string quartet with soprano solo, reveals Schoenberg's attempt to venture into the unknown territory of atonality using unconventional ensembles. Important works from the same period include Three Piano Pieces, Op. 11, Five Orchestral Pieces, Op. 16, and the monodrama Erwartung (Expectation), Op. 17. These works gained public recognition after Schoenberg signed a publishing contract with Universal Edition in Vienna in 1909. This company published not only Schoenberg's musical works but also his theoretical writings such as Harmonielehre (Theory of Harmony, 1911), and this relationship continued until his emigration to America.

However, these works, written in an avant-garde style, were extremely difficult for the Viennese audience of the time to accept. Given these circumstances, when it was decided that he would teach again in Berlin from the autumn of 1911, he left Vienna. The following year, in 1912, Pierrot Lunaire, Op. 21, was born. This work, not only atonal but also featuring the Sprechstimme technique of spoken-singing and an unusual instrumentation of soprano, piano, flute, clarinet, violin, and cello, greatly influenced not only contemporaries like Stravinsky but also later composers such as Boulez.

Due to military service in World War I, Schoenberg returned to Vienna in 1915. Although his creative output was limited during the war, he conceived various works, and the libretto for the unfinished oratorio Die Jakobsleiter (Jacob's Ladder) was completed during this period. In 1917, his pupil Berg began composing the opera Wozzeck, marking an era when atonal works were gradually gaining prominence. Nevertheless, it was still not easy for contemporary music of the time to be generally accepted and performed. Therefore, after the end of World War I in 1918, Schoenberg founded an organization called the “Society for Private Musical Performances” (Verein für musikalische Privataufführungen) with the aim of performing contemporary music. This organization included not only contemporary composers like Berg and Webern but also music lovers interested in their works. Despite its short active period from 1918 to 1922, a total of 154 works were performed in 117 concerts, including contemporary music as well as arrangements of works by Mahler and Johann Strauss II for chamber ensemble. Approximately a century after the “Viennese School” – Haydn, Mozart, and Beethoven – flourished in Vienna around 1800, Schoenberg and his two pupils, who rose to prominence in the same city, are today known as the “Second Viennese School” (or New Viennese School).

After the war ended and more than ten years had passed since the creation of his earliest atonal works, Schoenberg sought to establish a methodology for atonality. The result he arrived at was the twelve-tone technique. This compositional technique, which uses a basic tone row consisting of all 12 notes within an octave of the equal temperament scale, each used once, and then transforms it through retrograde, inversion, and other forms, became the foundation for the subsequent compositions of Schoenberg and his pupils Berg and Webern, and also served as a starting point for serial music in the latter half of the 20th century. Schoenberg's first work composed using the twelve-tone technique was Five Piano Pieces, Op. 23 (1920–23). The piano, tuned to equal temperament, was perfectly suited for experiments with the twelve-tone technique. All of Schoenberg's subsequent piano works, such as Suite, Op. 25 (1921–23), and Piano Pieces, Op. 33a/b (1929/31), were composed using the twelve-tone technique.

In the summer of 1925, Schoenberg moved to Berlin again after being offered a professorship in composition at the Prussian Academy of Arts (now the Berlin University of the Arts). He remained there until 1933, when anti-Jewish policies began to intensify with the Nazi seizure of power. During this approximately eight-year period in Berlin, works such as String Quartet No. 3, Op. 30, Variations for Orchestra, Op. 31, and the twelve-tone opera Von heute auf morgen (From Today to Tomorrow), Op. 32, were composed, and the creation of the unfinished opera Moses und Aron was also begun. Parallel to his creative work, he gave lectures across Europe on his own works and contemporary music. Particularly important was his 1933 lecture “Brahms the Progressive,” in which he described the innovativeness of Brahms's music using the term “developing variation.” Schoenberg later reorganized this lecture into an essay and included it in his collection of essays Style and Idea, published in 1950, in his final years. From this lecture analyzing Brahms's works, and also from his later autobiography, it is clear that Schoenberg consistently and thoroughly studied the works of classical and romantic composers. This attitude towards the works of great composers of the past is also evident in the fact that he arranged works by numerous composers such as Bach, Schubert, and Brahms, in addition to those of his contemporaries.

After staying in France in the summer of 1933, Schoenberg first headed to New York on October 31 of the same year. However, he soon moved to Los Angeles on the West Coast for health reasons. In his new home, he actively engaged in educational activities, teaching at the University of Southern California and the University of California, Los Angeles, and being invited as a visiting professor to the University of Chicago and the University of California, Santa Barbara. Although he reportedly expressed disappointment with the low level of American students, his pupils at the time included the young John Cage, who would later become an extremely important composer of contemporary music. In the early 1940s, due to the impact of World War II, numerous European artists, including Thomas Mann, Hanns Eisler, and Adorno, emigrated to Los Angeles, and Schoenberg befriended them. The protagonist of Thomas Mann's novel Doctor Faustus was modeled after Schoenberg, and the novel quotes actual conversations between Mann and Schoenberg.

During his American period, he often received commissions for works from local university orchestras, leading to the frequent composition of tonal works such as Theme and Variations, Op. 43. However, his only piano work after emigration, the Piano Concerto, Op. 42, as well as the Violin Concerto, Op. 36, and String Trio, Op. 45, were written using strict twelve-tone technique. He was also prolific in his writing, and various music theory books and composition theory books for beginners were produced during this era. His most important late work is likely A Survivor from Warsaw, Op. 46, for narrator, male chorus, and orchestra. This work, which depicts the Holocaust and is based on a man who survived a concentration camp in Warsaw during World War II, fully utilizes Schoenberg's compositional techniques, such as the twelve-tone technique and Sprechstimme.

Born in the late Romantic era as the next generation after Mahler and Strauss, Schoenberg, who endured two World Wars and continued to lead the nascent contemporary music movement, passed away in Los Angeles on July 13, 1951, due to an asthma attack.