Toru Takemitsu was born in Tokyo's Hongō district on October 8, 1930. His family relocated to Manchuria within a month; after his father's death in 1938, he returned to Japan for schooling, only to be conscripted at fourteen during the final stretch of World War II — an experience he described as "extremely bitter." During his military service, he first heard Western classical music, played secretly on a makeshift gramophone. Hospitalized with tuberculosis after the war, he listened extensively to Western music via US Armed Forces broadcasts. He studied briefly with composer Yasuji Kiyose from 1948, but was otherwise largely self-taught.

In 1951 he co-founded Jikken Kōbō (Experimental Workshop), an anti-academic, multidisciplinary collective, and independently developed musique concrète principles around 1948, roughly concurrent with Pierre Schaeffer's parallel development of the same techniques in France.

His international breakthrough came in 1958, when Igor Stravinsky, visiting Japan, happened to hear Takemitsu's 1957 Requiem for string orchestra during an NHK broadcast. Stravinsky insisted on hearing the piece in full and praised its "sincerity" and "passionate" writing, later inviting Takemitsu to lunch and, by most accounts, personally recommending him to Aaron Copland for a Koussevitzky Foundation commission — resulting in Dorian Horizon (1966), premiered by the San Francisco Symphony under Copland's baton.

Takemitsu credited John Cage, whose 1961 Japan premiere of Concert for Piano and Orchestra deeply impressed him, with helping him reconcile Western composition with Japanese tradition rather than moving away from it. He began studying the biwa and other traditional instruments from the early 1960s, and in 1967 the New York Philharmonic commissioned November Steps for its 125th anniversary — a landmark, genuinely difficult synthesis of biwa, shakuhachi, and full orchestra.

He also built one of the most prolific film-scoring careers of his generation, writing music for more than 100 films across less than 40 years. His work with Akira Kurosawa is best known, especially his score for Ran (1985), which won the Los Angeles Film Critics Award. For the film's central battle sequence, he wrote elegiac music that cuts off abruptly at a gunshot, leaving only the raw sound of the fighting — a deliberate compositional use of silence. He won the Grawemeyer Award for Music Composition in 1994, for Fantasma/Cantos.

He died in Tokyo on February 20, 1996, at 65, of pneumonia complicating a bladder cancer diagnosed the previous year, while still working toward an opera with novelist Barry Gifford that his illness prevented him from completing. He was posthumously awarded a Columbia University honorary doctorate and the Glenn Gould Prize. The Tokyo Opera City Concert Hall, opened in 1997, is dedicated to his memory, and the Toru Takemitsu Composition Award, established the same year, continues in his name.

Takemitsu's music synthesizes Western modernist technique — drawing directly on Debussy (his "great mentor"), Messiaen, and John Cage — with a deliberate, deepening engagement with traditional Japanese instruments and aesthetics, moving over his career from simple alternation between the two toward genuine integration. Many later works use a recurring E♭-E-A motif (spelling "Sea" in German solmization), appearing across his water-themed compositions.