Masahiko Satoh started on piano at five, not long after his family moved into a house in Tokyo's Sumida-ku that happened to have one. By 17 he was already working, accompanying singers and variety acts in Ginza cabarets, the kind of night-club apprenticeship that trained a generation of Japanese jazz musicians before conservatories caught up with the music. In 1959, at 18, he joined drummer George Kawaguchi's band alongside a young alto saxophonist named Sadao Watanabe, years before either man led a record under his own name. After Keio University, Satoh spent 1966 to 1968 studying composition and arranging at Berklee College of Music in Boston on a Downbeat Magazine scholarship, then came home and formed his own trio.

That trio's debut, "Palladium" (1969, Express), won Swing Journal magazine's Japan Jazz Award and set the template for the next several years: a free, percussive piano style pushed as far as it would go. 1971 was his breakout year for reasons that still define his reputation in reissue circles. "Amalgamation," credited to Masahiko Sato & the Soundbreakers, is a free-jazz and psychedelic-rock collision engineered by Rudy Van Gelder and produced by Creed Taylor, the same two names behind some of the most recognizable American jazz records of the era; it later placed at number seven on writer Julian Cope's "Japrocksampler" list of essential Japanese rock albums. That same year he performed at the Berlin Jazz Festival running a ring modulator through his piano, an unusual and early use of electronics for a jazz pianist in 1971, and he co-led "Metempsychosis" with percussionist Stomu Yamash'ta.

In 1973 Satoh wrote the psychedelic, free-jazz-and-funk score for the anime film "Belladonna of Sadness" (Kanashimi no Belladonna), directed by Eiichi Yamamoto, with vocals from his then-wife, actress Chinatsu Nakayama. Original pressings became scarce and expensive enough to be a running joke among collectors before Finders Keepers Records gave the album its first official reissue in 2020, a remastered LP that keeps the record "strictly Satoh" by dropping the one orchestral cue he didn't write, followed a year later by a limited 7" single. It remains one of the most-traded Satoh artifacts in reissue culture.

Satoh didn't treat electronics or genre-crossing as a phase. From 1981 to 2020, 39 years, he was head instructor of music theory, composition, and piano at Mesa House Music College, and in 2009 he created the chair of Non-idiomatic Improvisation at Tokyo University of the Arts. In between, he formed the world-folk-inflected ensemble Rantooga (1990) and co-led "Lunar Cruise" (1990) with percussionist Midori Takada, featuring Yellow Magic Orchestra's Haruomi Hosono on bass. He founded his own label, BAJ Records, in 1997, and has spent much of the 2000s recording a multi-album tribute series to percussionist Masahiko Togashi, the same drummer who played on "Palladium" back in 1969.

His most enduring recent collaboration has been with free-jazz saxophonist Peter Brötzmann and drummer Takeo Moriyama, a trio that first recorded together on 2012's "Yatagarasu" (Not Two Records) and reunited on stage at Cafe OTO in London during a 2019 Brötzmann festival. A separate set that same week, with Moriyama joined by bassist Leon Brichard and saxophonist Idris Rahman of Ill Considered rather than Brötzmann, surfaced five years later as "Live At Café OTO" (BBE Music, 2024). Satoh remains an active recording artist at 84: 2025 alone brought three new releases, "Thousand Leaves" (Trost Records), "Open Cluster" (on his own BAJ Records), and "AOI."

Satoh's earliest signature is a free, percussive piano attack developed in the late 1960s and pushed into genuinely experimental territory by 1971, the year he combined it with a ring modulator on stage in Berlin. That willingness to run his instrument through electronics, well before it was common practice for a jazz pianist, runs through his catalog from the Moog- and synthesizer-inflected records of the early 1970s to his 1990 ambient/fusion work with Midori Takada. His later work folds in traditional Japanese and world instrumentation and a spatial, unhurried sense of composition that critics have compared to composer Toru Takemitsu. He moves comfortably between structured composition (film scoring, big-band arranging, classical-adjacent pieces like "Based on Bach") and completely open improvisation, a range reflected directly in the chair of Non-idiomatic Improvisation he founded at Tokyo University of the Arts in 2009.