Eötvös was born in Odorheiu Secuiesc/Székelyudvarhely, Szeklerland, Transylvania (then part of Hungary, now in Romania). He studied composition in Budapest and Cologne. From 1962, he composed for film in Hungary. Eötvös played regularly with the Stockhausen Ensemble between 1968 and 1976. From 1979 to 1991, he was Musical Director and conductor of the Ensemble InterContemporain (EIC). From 1985 to 1988, he was principal guest conductor with the BBC Symphony Orchestra. He is principal guest conductor of the Gothenburg Symphony Orchestra since 2003. The recording of Berio’s Sinfonia with Peter Eötvös and London Voices (DG) received the BBC Music Magazine’s Award for “Technical excellence in recording” in 2006.
Eötvös's music shows the influence of a variety of composers. As director of the Ensemble InterContemporain, he was exposed to many exotic and respected samples of concert music, as is evidenced in the variety of timbres and sound-worlds within his music. Extended techniques such as over-pressure bowings coexist with lyrical folk songs, and synthesized sounds. Eötvös also is technologically competent, and provides detailed instructions on how to mix instruments for electronic manipulation or amplification. His first large scale compositions were for film. This often reflects on his later pieces in moments of atmospheric airiness. Two of his compositions for orchestra and voice, Atlantis and Ima, were inspired by Sándor Weöres' poem Néma zene.