Henri Pousseur studied at the Liège Conservatory from 1947 to 1952 with Pierre Froidebise and André Souris, both of whom encouraged him to study the music of Webern. He met Pierre Boulez in 1951 and Karlheinz Stockhausen two years later; the latter meeting gave rise to a period of work for Pousseur at the Cologne Studio, where he composed Séismogrammes, and his regular attendance at the Darmstadt Summer Courses starting in 1954. Pousseur’s first mature works (notably Symphonies for 15 Soloists, Quintet in Memory of Webern, Scambi for tape, created at the Milan Studio of Phonology (1957), Mobile for two pianos, and Répons) date from this period. He founded the Brussels Studio in 1958.

In the 1950s, Pousseur was an ardent defender of post-Webernian serialism, both in his compositions and his analytical writings. In contrast, the 1960s were shaped by the composer’s meeting with writer and art critic Michel Butor, with whom he would collaborate for the remainder of his career, and by the composition of Votre Faust and Couleurs croisées for orchestra (1967). It was also around this time that Pousseur finalised his “network theory,” which broadened his serialist approach through the assimilation of historical repertoire, as described in his book “The Apotheosis of Rameau” (1968). Pousseur taught at the University of Buffalo from 1966 to 1968, and co-founded the Wallonia Centre for Musical Research in 1970 with Pierre Bartholomée and Philippe Boesmans. In 1975, he composed Die Erprobung des Petrus Hebraïcus, a tribute to Schoenberg which also exists in a French-language version under the title Le procès du jeune Chien. In the same year, he became Director of the Liège Conservatory. From 1984 to 1987, he was Director of the Paris Institute of Musical Pedagogy, and was composer-in-residence at Louvain University from 1993 to 1998, during which he notably composed the cycle Aquarius-memorial, dedicated to Karel Goeyvarts.

Like Boulez and Stockhausen, Pousseur wrote extensively regarding theoretical aspects of his music, authoring numerous highly influential articles on the subject. He was also outspoken on questions of musical aesthetics, and was one of only a handful of musicians to have proposed meaningful responses to Nicolas Ruwet’s “Contradictions within the Serial Language” and Lévi-Strauss’s famous “Overture” to The Raw and the Cooked.

With the exception of a handful of works published by Universal Edition (Vienna), Pousseur’s scores are published by Suvini Zerboni (Milan). His archives are housed at the Paul Sacher Foundation in Basel.