Raised in Sapporo, Hayasaka was a self-taught composer. He became fast friends with Akira Ifukube, another autodidact, later famous for his music accompanying Toho's movie monsters. Together they organized the Shin Ongaku Renmei (New Music League) in 1933. In 1935 Hayasaka composed his first orchestral piece, the award-winning Futatsu no sanka e no zensokyoku (Prelude to Two Hymns). His next orchestral piece, Ancient Dance, won the Weingartner Prize in 1938. In 1939, he moved to Tokyo in order to begin his long career as a film music composer. His first score was for Ribbon o musubu fujin (The Lady Ties a Ribbon) directed by Satsuo Yamamoto in 1939. Hayasaka produced music for over 90 films during his career, many of them noted and award winning classics. But he simultaneously continued his creation of concert music, producing the orchestral piece Saho no mai to uho no mai (Left Dance and Right Dance, 1942), his well-known Four unaccompanied songs to poems by Haruo for solo soprano (1944), and a Piano Concerto (1946). In 1948, he scored Yoidore tenshi (Drunken Angel), his first film for director Akira Kurosawa. Sophisticated overdubs were called for when no tape recorders were to be had. In one scene, 12 songs had to overlap in precise synchronization with the imagery; this could be accomplished only after many takes involving cued vinyl records. The exhausted technical director was found weeping in a corridor during a break. From 1947 until 1953, Hayasaka was a member of the Shin Sakkyokuha Kyokai and in 1950 founded the Association of Film Music. During this time, he wrote the Capriccio for winds and piano (1949), a String Quartet (1950), and the Metamorphosis for orchestra (1953). He also scored Kurosawa's famous Rashomon (1950), Hakuchi (The Idiot, 1951), and the exquisite Ikiru (1952). For Kenji Mizoguchi, he created the eerie sounds for the ghost story Ugetsu monogatari (Tales of a Pale and Mysterious Moon After the Rain, 1953). In the year 1954, for another Kurosawa classic Shichinin no samurai (The Seven Samurai), Hayasaka conceived a humorous theme scored for bassoon, piccolo, and bongos to express the apishness of actor Toshiro Mifune's character. This was accomplished even though Hayasaka's persistent tuberculosis began to worsen as he worked through over 300 orchestral cues in a two-month period. For this effort, he received a stand-alone credit on the screen, something never previously accorded a composer in a Japanese film. He also supplied music for Mizoguchi's Chikamatsu monogatari (The Crucified Lovers) and Sansho dayu (Sansho the Bandit), and Toshio Sugie's Mitsuyu-sen (The Black Fury) in 1954. During 1955, he composed Yukara for orchestra, a suite based on an epic of the island peoples called the Ainu, and the film scores for Mizoguchi's twelfth century warrior epic Shin heike monogatari (New Tales of the Taira Clan) and Kurosawa's Ikimono no kiroku (I Live in Fear). Hayasaka finally succumbed to tuberculosis shortly after completing Kurosawa's anti-atomic bomb film Record of a Living Being.