Stu Hacohen was born in 1929 in Pernik, Bulgaria, where he learned accordion on his older brother's instrument and played with a local Romani ensemble, absorbing rhythmic vocabulary — Bulgarian meters in 9/8 and 13/8 — that later became a signature of his arranging. He immigrated to Israel in 1949 at twenty and was taken in by conductor Erich Teich as a multi-instrumentalist in the Israeli Air Force Orchestra, adding contrabass, saxophone and piano to the accordion he already played. In the early-to-mid 1950s he played in Maurice "Pisi" Osherowitz's house orchestra at Tel Aviv's Dan Hotel, becoming self-taught in jazz through records and literature; fellow jazz veteran Albert Piamenta later called him "one of the Jews who really did play jazz here."

He built a long career as an Israeli arranger and conductor: music for Shimon Israeli's 1960 one-man show, the Armored Corps entertainment troupe's 1961 program, the orchestra on Arik Einstein's 1966 debut album Shar Bishvilcha, Georges Brassens adaptations for Yossi Banai's 1969 show Ein Ahavot Smechot — Banai became a close personal friend, and Hacohen served as that show's musical director — and Aliza Azikri's 1970 record. Around 1967 he met vocalist Rimona Francis; they married and became a lasting musical partnership. Their first joint recording, a Kol Israel radio version of Mattityahu Shelem's song "Shibolet BaSade," had Francis singing vocalise — using her voice as an instrument to recreate jazz horn solos by Charlie Parker and Clifford Brown note for note, well enough that friends nicknamed her "the trumpet." That approach became the basis of two 1969 LPs: Rimona Francis With Stu Hacohen's Orchestra (Israphon), marketed explicitly as "Jazz Vocalise" and drawing on the same Bulgarian-meets-jazz fusion Hacohen had carried since Pernik, and Badabada... (Hed-Arzi), a second, more Latin/Afro-Cuban-facing record from the same year.

Dizzy Gillespie met the couple during a visit to Israel and reportedly encouraged their mid-1970s move to the United States, where Hacohen arranged Francis's self-titled 1978 album for the respected German jazz label MPS, recorded in New York with a band including pianist Jasper van't Hof, guitarist Barry Finnerty and saxophonist Leszek Żądło, and produced by Joachim Ernst Berendt. They returned to Israel in the late 1980s, and Hacohen devoted himself primarily to teaching, becoming an influential figure in Israeli jazz education — his most prominent student, saxophonist Eli Degibri, played at his funeral. In his final years, as a severe degenerative neuromuscular illness made playing difficult, he turned to painting portraits of jazz icons — Coltrane, Sonny Stitt, Dizzy Gillespie. He died on August 13, 2006, at 77, and was buried at Kibbutz Einat; Francis has said his last words concerned seeing his late friend Yossi Banai again soon.

Hacohen's defining move was importing Bulgarian and Romani folk rhythm — odd meters like 9/8 and 13/8 — directly into a jazz big-band arranging vocabulary, at a time when Israeli jazz was still finding its own voice separate from American models. The vocalise concept he built around Rimona Francis's voice, using it as a horn substitute rather than a conventional lyric instrument, was a genuine and specific innovation for the Israeli scene of 1969, and it's the single idea his recorded work is most remembered for.