Born in 1935 in Stuttgart, he studied piano with Jürgen Uhde, theory and counterpoint with Johann Nepomuk David at the Conservatoire in Stuttgart (1955–58), as well as composition with Luigi Nono in Venice (1958–60). The first public performances of his works took place in 1962 at the Venice Biennale and at the International Summer Courses for New Music in Darmstadt. In 1965 he worked at the electroacoustic studio of Ghent University, and in 1966 he began his several-decade-long teaching practice, collaborating on a more or less regular basis with numerous universities and new music hubs in Germany and elsewhere. He coordinated courses for composers in Darmstadt (1972), taught a composition masterclass at the University of Basel (1972–73), worked for three years at the High School of Music in Hanover (1976–79; he was awarded an honorary doctorate of this school in 2001), lectured at the Cursos Latinoamericanos de Música Contemporânea in Brazil and the Dominican Republic (1972, 1982), and taught composition at the High School of Music in Stuttgart (1981–99). From the 1980s onwards he conducted seminars and workshops on music composition throughout Europe, in both Americas, Russia, China, and Japan. In 2008 he was a guest lecturer at Harvard University, and in 2010 at the High School of Music in Basel and the Royal College of Music in London. He was also a personal judge of the Toru Takemitsu Composition Award. He has received numerous awards for his compositions, including the City of Munich Culture Prize (1965), Composition Prize of the City of Stuttgart (1968), Bach Prize (Hamburg, 1972), Ernst von Siemens Music Prize (1997), Royal Philharmonic Society Award (London 2004, for String Quartet no. 3 Grido), Leone d’Oro of the Venice Biennale (2008), BBVA Frontiers of Knowledge Award (2011), Order of Merit of the Federal Republic of Germany (2012), GEMA Autorenpreis (2015), and Hans Christian Andersen Award for his opera The Little Match Girl (2016). Lachenmann is a member of Academies of Arts in Berlin, Hamburg, Leipzig, Mannheim, and Munich, as well as the Royal Flemish Academy of Belgium for Science and the Arts. His discography comprises several dozen CDs and numerous analogue records. His music has been performed at all major international festivals as well as in concerts worldwide. His 80th birthday in 2015 was celebrated with a series of concerts titled Lachenmann Perspectives, featuring leading European orchestras, which performed twenty of the composer’s works. 

Selected works (since 1990): “...zwei Gefühle...”, Musik mit Leonardo for two speakers and small orchestra (1992), Air for percussion and large orchestra (rev. 1994), The Little Match Girl, music theatre to a libretto after Hans Christian Andersen, Leonardo da Vinci and Gudrun Ensslin (1990–96), Nun for male choir, flute, trombone and large orchestra (1998–2003), Serynade for piano (1998–2000), String Quartet no. 3 Grido (2001), Schreiben for orchestra (2003–4), Double (Grido II) for string orchestra (2004), Concertini for instrumental ensemble (2005–6), Raumfahrer for orchestra (2007), Got Lost for soprano and piano (2007–8), Marche fatale, version for orchestra (2016), My Melodies for eight horns and orchestra (2016–19).