Salonen studied horn, conducting and composition at the Sibelius Academy in Helsinki. Later, he studied with the composers Franco Donatoni and Niccol˛ Castiglioni. Originally he dedicated himself to composing but in 1983 he undertook a performance of Mahler's third symphony with the Philharmonia Orchestra in London at short notice, and it launched his career as a conductor. He was subsequently principal guest conductor of the Philharmonia from 1985 to 1994.
Principal conductor of the Swedish Radio Symphony Orchestra since 1985 and music director of the Los Angeles orchestra since 1991, Salonen is renowned for his dedication to performing and recording contemporary music. His 1985 world premiere recording of Witold Lutoslawski's Symphony No. 3 won the 1985 Gramophone Award for Best Contemporary Recording.
Among Salonen's compositions are ...auf den ersten blick und ohne zu wissen... (1980, a saxophone concerto with a title taken from Franz Kafka's The Trial), Floof for soprano and ensemble (1982, on texts by Stanislaw Lem) and the orchestral L.A. Variations (1996). In order to devote more time to composition, Salonen took a year's sabbatical from conducting in 2000, during which time wrote a work for solo horn (Concert ╔tude, the competition piece for Lieksa Brass Week), a work for the cellist Anssi Karttunen and sinfonietta, and an orchestral piece.