Leroy Jenkins was born on Chicago's South Side on March 11, 1932, and started violin at eight, in 1940, under a teacher he called 'Fess: O.W. Frederick, who ran the string program at Ebenezer Baptist Church. His mother bought his first instrument, a small red violin, from Montgomery Ward for twenty-five dollars, and he studied with Frederick for six years while playing regularly at St. Luke's Baptist Church. In 1946 he entered DuSable High School and fell under Walter Dyett, the bandmaster whose alumni list runs from Nat King Cole to Johnny Griffin. Dyett moved him through clarinet and bassoon and into the concert band before he graduated in 1950. Formal study stopped there for six years. Jenkins went back to school in 1956 at Florida Agricultural and Mechanical University in Tallahassee on a music scholarship, took classical violin with Bruce Hayden, and finished a music education degree in 1961. Hayden mattered enough that Jenkins called him "the most perfect musician I ever met" and dedicated his first solo album to him sixteen years later.

The degree led straight into teaching. From 1961 to 1965 Jenkins worked in Mobile, Alabama as coordinator for string instruments in the city's segregated Black school system, building string programs across thirteen schools and playing classical recitals on the side while he worked out his own approach to improvising. He came back to Chicago in 1965 and taught in the public school system there until 1969. That return coincided with the founding of the Association for the Advancement of Creative Musicians, and Jenkins turned up at an AACM event, started sitting in on rehearsals led by pianist Muhal Richard Abrams, and joined. His recording debut came on Abrams's Levels and Degrees of Light, cut in 1967 and issued by Delmark in 1968. In the same period he recorded with Anthony Braxton and trumpeter Leo Smith on 3 Compositions of New Jazz (Delmark, 1968), the trio that would carry him out of Chicago.

Jenkins, Braxton, Smith and drummer Steve McCall left for Paris in 1969, part of the AACM exodus that put Chicago's new music in front of European audiences and the BYG Actuel label's microphones. Jenkins recorded there with Braxton, with bassist Alan Silva's Celestrial Communication Orchestra on Luna Surface, and with Archie Shepp. The Braxton/Jenkins/Smith trio cut Silence in Paris on July 18, 1969. He also crossed paths with Philly Joe Jones and Ornette Coleman during the same stretch. Coleman turned out to be the decisive contact: when Jenkins moved to New York in 1970, he lived for several months in Coleman's Artists House loft, and Coleman supervised the recording of the group Jenkins convened with Braxton, Smith, McCall, Abrams and bassist Richard Davis. Billed as the Creative Construction Company, that sextet played the Washington Square Methodist Church, the Greenwich Village room everyone called the Peace Church, on May 19, 1970. Muse Records held the tapes for years before issuing them as two volumes in 1975 and 1976.

Later in 1970, over candlelight at Liberty House on Bleecker Street, Jenkins and bassist Sirone talked out the group that would define his reputation. The Revolutionary Ensemble, completed by percussionist and pianist Jerome Cooper, was built as a cooperative with no designated leader, and it lasted roughly six years on that principle. Its records track a trio thinking out loud: Vietnam, recorded at the Peace Church in March 1972 and released by ESP-Disk that year; Manhattan Cycles, taped live on New Year's Eve 1972 and issued by India Navigation; The Psyche on the group's own RE Records; The People's Republic, cut over three days in December 1975 at Kendun Recorders in Burbank for A&M's Horizon imprint, the closest the trio ever came to a major label; and Revolutionary Ensemble, recorded live at Moosham Castle in Austria in August 1977 for Enja. George E. Lewis later called them "one of the signal groups of the period." They broke up in 1977, reunited in 2004 for And Now... on Pi Recordings, and left two more live documents, Beyond the Boundary of Time and Counterparts, issued after Jenkins was gone.

The New York loft years put Jenkins in a wide orbit. He recorded with Alice Coltrane on Universal Consciousness (1971) and World Galaxy (1972), with Archie Shepp on Things Have Got to Change, Attica Blues and The Cry of My People, with Carla Bley on Escalator over the Hill, with Don Cherry on Relativity Suite, with Paul Motian on Conception Vessel, and with Rahsaan Roland Kirk, Dewey Redman and Grachan Moncur III. His own largest score of the decade, For Players Only, was commissioned by the Jazz Composer's Orchestra in 1974, premiered across four workshop concerts at Columbia University's Wollman Auditorium that January, recorded on January 30, 1975, and released on JCOA. Its roster shows how far his network reached: Braxton, Smith, Dave Holland, Sirone, Cooper, Redman, cellist Diedre Murray, guitarist James Emery, and two St. Louis players out of the Black Artists Group, trombonist Joseph Bowie and drummer Charles "Bobo" Shaw. That September he walked into Studio 77 at 77 Greene Street, the Soho room drummer Rashied Ali had built into a club and studio, and cut a violin-and-drums duo with him on September 18, 1975. Ali mixed it the next day and put it out on his own Survival Records in 1976 as Swift Are the Winds of Life, with liner notes by Stanley Crouch.

From 1977 Jenkins built a leader catalog with unusual variety of format. Solo Concert (India Navigation, 1977) came from an unaccompanied recital at the Washington Square Church on January 11, 1977. The Legend of Ai Glatson (Black Saint, 1978), cut in Milan with pianist Anthony Davis and drummer Andrew Cyrille, includes an elegy titled "Albert Ayler (His Life Was Too Short)" for the saxophonist Albert Ayler. Space Minds, New Worlds, Survival of America (Tomato, 1979) added trombonist George Lewis and Richard Teitelbaum's Moog synthesizers, and instructed the listener to play side A loud and side B soft. He recorded a live duo with cellist Abdul Wadud in Cremona in September 1979, released as Straight Ahead / Free at Last on Italy's Red Record, and another with Abrams, taped on his forty-fifth birthday in 1977 and issued five years later as Lifelong Ambitions. Mixed Quintet (Black Saint, 1983) dropped the rhythm section entirely for winds: J.D. Parran, Marty Ehrlich, James Newton and John Clark. In the early 1980s he assembled Sting, an electric band with two violins, two guitars, electric bass and drums, whose Urban Blues was recorded live at Sweet Basil in January 1984 with violinist and singer Terry Jenoure, guitarists Brandon Ross and James Emery, bassist Alonzo Gardner and drummer Kamal Sabir.

As the jazz mainstream turned conservative in the late 1980s, Jenkins pushed further into notated music and the theater. Hans Werner Henze commissioned an opera for the Munich Biennale, and Mother of Three Sons, on a libretto by Ann T. Greene with choreography and direction by Bill T. Jones, premiered in Munich in 1990, then went to New York City Opera in 1991 and Houston Grand Opera in 1992, collecting a Bessie Award. The stage works kept coming: Fresh Faust, a rap opera for Boston's Institute of Contemporary Art; The Negros Burial Ground, a cantata presented by The Kitchen; The Three Willies, staged at Philadelphia's Painted Bride Art Center and The Kitchen; and Coincidents, written with librettist Mary Griffin for Roulette. He kept recording alongside all of it: Leroy Jenkins Live! from P.S. 122 in 1992, Themes & Improvisations on the Blues (CRI, 1994) with the Soldier String Quartet, Henry Threadgill, Don Byron and Marty Ehrlich from a Merkin Concert Hall program, Out of the Mist (1997) and then Equal Interest (OmniTone, 1999), both with AACM saxophonist Joseph Jarman and pianist Myra Melford, and The Art of Improvisation (Mutable Music, 2005) by his last band, Leroy Jenkins' Driftwood, with pipa player Min Xiao-Fen, pianist Denman Maroney and percussionist Rich O'Donnell.

Recognition arrived across both halves of the career. DownBeat named him Talent Deserving Wider Recognition in 1974, and its critics and readers gave him the violin category in 1972 and 1987; France's Jazz Magazine poll followed in 1979. The Fromm Foundation gave him a composition grant in 2003, the Guggenheim Foundation a fellowship in 2004, and the ASCAP Foundation its Rudolf Nissim Prize in 2006 for Concerto for Improvised Violin and Orchestra. Jenkins was 74 when he lost a fight with lung cancer on February 24, 2007. Two operas were unfinished on his desk: Bronzeville, a history of Chicago's South Side, and Minor Triad, a music drama about Paul Robeson, Lena Horne and Cab Calloway.

The violin reached jazz's avant-garde late and mostly by way of swing, through Eddie South, Stuff Smith and Ray Nance, and Jenkins named South alongside Jascha Heifetz as his early models before John Coltrane and Ornette Coleman redirected him. What he did with the instrument after 1965 was less an extension of that lineage than a re-founding: sawing, bending and snapping the strings, working the bridge and the wood, playing at volumes and in registers the classical training had never been aimed at, and doing all of it without giving up either his tone or his blues phrasing. His teaching-degree literacy was part of the equipment rather than a hedge against it, which is why Mixed Quintet can sit next to Vietnam in the same catalog. Inside the Revolutionary Ensemble the same instincts produced what the scholar Bob Gluck called "parallel play," three musicians pursuing separate lines that add up to one structure without anyone conducting. The composer Carman Moore heard the split personality as a single thing, describing "Brahms or Tchaikovsky virtuosity" surfacing in the middle of a blues-based passage. Critics agreed early and stayed agreed: DownBeat's polls put him at the top of the violin category in 1972 and again in 1987, and the reviews of Solo Concert and The Legend of Ai Glatson in the late 1970s treated an unaccompanied free-jazz violin recital as a plausible thing to release.