After being reclaimed by his parents in the late 1880s, in 1893 young Edgard was forced to relocate with them to Turin, Italy, in part, to live amongst his paternal relatives, since his father was of Italian descent. It was there that he had his first real musical lessons, with the long-time director of Turin’s conservatory, Giovanni Bolzoni. In 1895, he composed his first opera, Martin Pas, which has since been lost. Now in his teen years, Varèse, influenced by his father, an engineer, enrolled at the Polytechnic of Turin and started studying engineering, as his father disapproved of his interest in music and demanded an absolute dedication to engineering studies. This conflict grew greater and greater, especially after the death of his mother in 1900, until 1903 when Varèse left home for Paris.

In 1904, he commenced his studies at the Schola Cantorum (founded by pupils of César Franck), where his teachers included Albert Roussel. Afterwards, he went to study composition with Charles-Marie Widor at the Paris Conservatoire. In this period, he composed a number of ambitious orchestral works, but these were only performed by Varèse in piano transcriptions. One such work was his Rhapsodie romane, from about 1905, which was inspired by the Romanesque architecture of the cathedral of St. Philibert in Tournus. In 1907, he moved to Berlin, and in the same year, he married the actress Suzanne Bing, with whom he had one child, a daughter. They divorced in 1913.

During these years, Varèse became acquainted with Erik Satie and Richard Strauss, as well as with Claude Debussy and Ferruccio Busoni, who particularly influenced him at the time. He also gained the friendship and support of Romain Rolland and Hugo von Hofmannsthal, whose Œdipus und die Sphinx he began setting as an opera that was never completed. On 5 January 1911, the first performance of his symphonic poem Bourgogne was held in Berlin.

After being invalided out of the French Army during World War I, he moved to the United States in December 1915.

In 1918, Varèse made his debut in America conducting the Grande messe des morts by Berlioz.

It was also about this time that Varèse began work on his first composition in the United States, Amériques, which was finished in 1921 but would remain unperformed until 1926, when it was premiered by the Philadelphia Orchestra, conducted by Leopold Stokowski (who had already performed Hyperprism in 1924 and would premiere Arcana in 1927). Virtually all the works he had written in Europe were either lost or destroyed in a Berlin warehouse fire, so in the U.S. he was starting again from scratch. The only surviving work from his early period appears to be the song Un grand sommeil noir, a setting of Paul Verlaine. (He still retained Bourgogne, but destroyed the score in a fit of depression many years later.)

At the completion of this work, Varèse, along with Carlos Salzedo, founded the International Composers’ Guild, dedicated to the performances of new compositions of both American and European composers. The ICG’s manifesto in July 1921 included the statement, “[t]he present day composers refuse to die. They have realised the necessity of banding together and fighting for the right of each individual to secure a fair and free presentation of his work.” In 1922, Varèse visited Berlin where he founded a similar German organisation with Busoni.

He took American citizenship in October 1927. After arriving in the USA Varèse commonly used the form ‘Edgar’ for his first name but reverted to ‘Edgard’, not entirely consistently, from the 1940s.

In 1928, Varèse returned to Paris to alter one of the parts in Amériques to include the recently constructed ondes Martenot. Around 1930, he composed Ionisation, the first Classical work to feature solely percussion instruments. Although it was composed with pre-existing instruments, Ionisation was an exploration of new sounds and methods to create them.

In 1928, when he was asked about jazz, he said it was not representative of America but instead was, “a negro product, exploited by the Jews. All of its composers here are Jews,” meaning Gruenberg and Boulanger students including Copland and Blitzstein.

In 1931, he was the best man at the wedding of his friend Nicolas Slonimsky in Paris. In 1933, while still in Paris, he wrote to the Guggenheim Foundation and Bell Laboratories in an attempt to receive a grant to develop an electronic music studio. His next composition, Ecuatorial, was completed in 1934, and contained parts for two fingerboard Theremin cellos, along with winds, percussion, and a bass singer. Anticipating the successful receipt of one of his grants, Varèse eagerly returned to the United States to realize his electronic music. Slonimsky conducted its premiere in New York on April 15, 1934.

Varèse soon left New York City for Santa Fe, San Francisco and Los Angeles. In 1936, he wrote his solo flute piece, Density 21.5. He also promoted the theremin in his Western travels, and demonstrated one at a lecture at the University of New Mexico in Albuquerque on November 12, 1936. (The University has an RCA theremin in its archives which may be the same instrument.) By the time Varèse returned to New York in late 1938, Theremin had returned to Russia. This devastated Varèse, who had hoped to work with him on a refinement of his instrument.

On several occasions, Varèse speculated on the specific ways in which technology would change music in the future. In 1936, he predicted musical machines that would be able to perform music as soon as a composer inputs his score. These machines would be able to play “any number of frequencies,” and therefore the score of the future would need to be “seismographic” in order to illustrate their full potential. In 1939, he expanded on this concept, declaring that with this machine “anyone will be able to press a button to release music exactly as the composer wrote it—exactly like opening up a book.” Varèse would not realize these predictions until his tape experiments in the 1950s and 60s.

This second project was to be a choral symphony entitled Espace. In its original conception, the text for the chorus was to be written by André Malraux. Later, Varèse settled on a multi-lingual text of hieratic phrases to be sung by choirs situated in Paris, Moscow, Beijing and New York City, synchronized to create a global radiophonic event. Varèse sought input on the text from Henry Miller, who suggests in The Air-Conditioned Nightmare that this grandiose conception—also ultimately unrealized—eventually metamorphosed into Déserts. With both these huge projects Varèse felt ultimately frustrated by the lack of electronic instruments to realize his aural visions. Nevertheless, he used some of the material from Espace in his short Étude pour espace, virtually the only work that had appeared from his pen for over ten years when it was premiered in 1947. According to Chou Wen-chung, Varèse made various contradictory revisions to Étude pour espace which made it impossible to perform again, but the 2009 Holland Festival, which offered a ‘complete works’ of Varèse over the weekend of 12–14 June 2009, persuaded Chou to make a new performing version (using similar brass and woodwind forces to Déserts and making use of spatialized sound projection). This was premiered at the Gashouder concert hall, Westergasfabriek, Amsterdam by Asko/Schönberg Ensemble and Cappella Amsterdam on Sunday 14 June, conducted by Péter Eötvös.

He was approached by music producer Jack Skurnick resulting in EMS Recordings #401. The record was the first release on LP of Integrales, Density 21.5, Ionisation and Octandre and featured René Le Roy, flute, the Juilliard Percussion Orchestra and the New York Wind Ensemble conducted by Frederic Waldman. Ionisation had also been the first work by Varèse to be recorded in the 1930s, conducted by Nicolas Slonimsky and issued on 78rpm Columbia 4095M. Likewise, Octandre was recorded and issued on 78rpm discs in the later 1930s, complete (New Music Quarterly Recordings 1411) and as an excerpt (3rd movement, Columbia DB1791 in Volume V of their History of Music). Le Roy was the soloist also on a 1948 (78rpm) recording of Density 21.5 (New Music Recordings 1000).

Varèse’s emphasis on timbre, rhythm, and new technologies inspired a generation of musicians who came of age during the 1960s and 1970s. One of Varèse’s most devoted fans was the American guitarist and composer Frank Zappa, who, upon hearing a copy of The Complete Works of Edgard Varèse, Vol. 1 (there was never a Vol. 2) became obsessed with the composer’s music. The first album Zappa heard was released on LP by EMS Recordings in 1950, and included Intégrales, Density 21.5, Ionisation, and Octandre.

The conductor of modern music, Robert Craft, recorded two LP volumes of Varèse music in 1958 and 1960 with percussion, brass, and wind sections from the Columbia Symphony Orchestra for Columbia Records (Columbia LP catalog Nos.MS6146 and MS6362). These recordings brought Varèse wide attention among musicians and musical aficionados beyond his immediate sphere. Much of the percussion music of George Crumb in particular owes a debt to such Varèse works as Ionisation and Intégrales.

When, in the late 1950s, Varèse was approached by a publisher about making Ecuatorial available, there were very few theremins—let alone fingerboard theremins—to be found, so he rewrote/relabelled the part for ondes Martenot. This new version was premiered in 1961. (Ecuatorial has been performed again with fingerboard theremins in Buffalo, NY in 2002 and at the Holland Festival, Amsterdam, in 2009.)

In 1962, he was asked to join the Royal Swedish Academy of Music, and in 1963 he received the premier Koussevitzky International Recording Award.

In 1965, Edgard Varese was awarded the Edward MacDowell Medal by the MacDowell Colony.