Paul Bley was born Hyman Bley on November 10, 1932, in Montreal, the son of Joseph Bley, an embroidery-factory owner, and Betty Marcovitch, an immigrant from Romania. He started on violin at five and switched to piano at seven; around age thirteen he changed his first name to Paul, reasoning, as he told interviewers later in life, that it would go over better with girls. He was a serious student as well as a precocious one, earning a junior diploma from the McGill Conservatory at eleven, and by his teens he was touring with visiting American bands and organizing his own. In 1949, Oscar Peterson invited the young Montrealer to fill out a booking at the city's Alberta Lounge; the following year Bley moved to New York to study at Juilliard, and he stayed in the United States for the rest of his career while keeping his Canadian citizenship.

New York quickly became a proving ground. Bley founded the Montreal Jazz Workshop while still shuttling between the two cities, and in 1953 he brought Charlie Parker in to play and record with the group; that same year the Shaw Agency booked Bley's trio to tour behind Lester Young, billed in advertisements as "Lester Young and the Paul Bley Trio," and he also worked alongside Ben Webster. His recording debut as a leader followed almost immediately: Introducing Paul Bley, cut November 30, 1953, and released the next year on Debut Records, the label Charles Mingus had co-founded with Max Roach. Mingus played bass and produced; Art Blakey played drums — both men are profiled separately on JazzProfiles.com, and both were simply hired sidemen on a twenty-one-year-old's first date, not yet the towering figures they'd become.

Bley married the composer Karen Borg — soon renamed Carla Bley — in Los Angeles in 1957. Their marriage lasted only a few years, but the creative partnership long outlasted it: Carla became one of the defining composers of the jazz avant-garde, and Bley kept returning to her books for decades, eventually devoting an entire 1992 album, Paul Bley Plays Carla Bley, to her music alone. It was also in Los Angeles, fronting the house band at the Hillcrest Club, that Bley made his most consequential hire: by 1958 his quintet included alto saxophonist Ornette Coleman, trumpeter Don Cherry, bassist Charlie Haden, and drummer Billy Higgins — the same players, minus Bley, who would record The Shape of Jazz to Come for Atlantic the following year and detonate free jazz into the wider jazz world. A tape of that October 1958 Hillcrest engagement surfaced decades later; by the time it reached wide release, in 2007, it was billed to "Ornette Coleman Quintet With Don Cherry & Paul Bley" — Coleman's fame had, fairly enough, overtaken Bley's role as the man who'd hired him.

Through the early 1960s Bley toured Europe with a trio led by reedman Jimmy Giuffre alongside bassist Steve Swallow, recordings now regarded as landmarks of early chamber-jazz improvisation, and turned up on Sonny Rollins's Sonny Meets Hawk! opposite Coleman Hawkins — a session Pat Metheny later singled out for Bley's solo on "All the Things You Are." In 1964 he was instrumental in founding the Jazz Composers Guild with Bill Dixon, Cecil Taylor, Archie Shepp, Roswell Rudd, and others, a cooperative that staged the concert series known as the October Revolution in Jazz. The same period produced the first recordings of his long, intermittent partnership with bassist Gary Peacock — whose own JazzProfiles.com profile covers their nearly four-decade collaboration in full — beginning with sessions in 1963 that, combined with a separate 1968 date, became Paul Bley With Gary Peacock, released in 1970 as only the third title in the entire ECM catalog.

After divorcing Carla Bley in 1967, Bley married the composer and vocalist Annette Peacock, and the relationship pushed him toward the instrument he's arguably as remembered for as the piano: the synthesizer. Annette had persuaded Robert Moog to lend her one of his earliest modular prototypes around 1969, and on December 26 of that year the two staged what's often cited as the first live synthesizer performance in jazz, at Philharmonic Hall in New York, touring afterward as the Bley-Peacock Synthesizer Show. Their duo recordings Improvisie (with Dutch drummer Han Bennink) and Dual Unity, both drawn from 1971 sessions, document the sound directly. Bley never abandoned the piano for it — 1972's Open, to Love, his first date for a young producer named Manfred Eicher, is a solo-piano album still cited as the clearest entry point into his whole catalog — but the synthesizer work marked him, alongside Annette, as one of jazz's first serious explorers of electronic instruments.

In 1974 Bley and his second wife, video artist Carol Goss, founded Improvising Artists Inc. (IAI) to document his own work and that of musicians including Jimmy Giuffre, Lee Konitz, Dave Holland, and Steve Lacy; one IAI session, Jaco, gave guitarist Pat Metheny his recorded debut alongside bassist Jaco Pastorius. A 1976 tour of Japan with Peacock produced the live Japan Suite, cut with drummer Barry Altschul at a Yamaha festival — a date Peacock later credited with helping pull him back toward jazz full-time after a long personal sabbatical. Through the 1980s and '90s Bley recorded prolifically and mostly for small independent labels — Soul Note, SteepleChase, Owl, Justin Time — duo dates with Chet Baker (Diane) and a reunion with Charlie Haden and Paul Motian (The Montreal Tapes) among them, while continuing to revisit both ex-wives' songbooks and, in 1999, reuniting with Peacock and Motian one more time for ECM's Not Two, Not One. He also taught part-time at the New England Conservatory, mentoring musicians including pianist Satoko Fujii.

Bley's later honors included Canada's National Archives acquiring his personal papers in 2001 and his appointment to the Order of Canada in 2008; he kept releasing solo-piano records into that decade, among them Solo in Mondsee for ECM. His final public performances came in 2010 — a solo concert in Paris and a duo reunion with Charlie Haden at New York's Blue Note. He died of natural causes at his home in Stuart, Florida, on January 3, 2016, at eighty-three. Three years later, ECM released When Will the Blues Leave, an archival concert recording of the Bley/Peacock/Motian trio taped in Lugano in 1999 — a last document of a partnership that had run, on and off, for the better part of four decades.

Bley's musical identity was shaped as much by the composers he married as by any pianist he studied: Carla Bley's oblique, melodically askew tunes gave his early-1960s trios their repertoire, and Annette Peacock's songs — along with her own pioneering work fusing voice and Moog synthesizer — pulled him toward electronics and toward a starker, more spacious improvisational language in the late 1960s and '70s. His trio work, especially the long-running partnership with Gary Peacock, treated bass and drums as fully improvising, harmonically independent voices rather than a supporting rhythm section, a model that fed directly into how Keith Jarrett would later build his own trio with Peacock and Jack DeJohnette. Bley was also, unusually for a major improviser, an institution-builder and employer: he hired the future Ornette Coleman quartet into his own band before their fame, co-founded the Jazz Composers Guild, and ran his own label and video-production company, IAI, with Carol Goss, at a moment when few musicians controlled that much of their own documentation.