His death was confirmed by his son, Felix.
Mr. Gruntz's work as both a maker and presenter of music was defined by its inclusiveness. As Duke Ellington and others had, Mr. Gruntz wrote and arranged music specifically for the individual members of his band and gave them generous solo time. The music reflected much of jazz history, from Ellington and Basie through Gil Evans and beyond, into free improvisation, funk, electronics and, on the 1992 record "Blues 'N Dues Et Cetera," vinyl-scratching D.J.'s.
The list of musicians who toured and recorded with different iterations of the George Gruntz Concert Jazz Band from 1972 to 2012 was a roll call of innovation and international style. Its members included the trumpeters Jon Faddis and Woody Shaw, the saxophonists Joe Henderson and Lee Konitz, the drummers Elvin Jones and Paul Motian, and many others. When Miles Davis revisited his old collaborations with Gil Evans at the Montreux Jazz Festival in 1991, with Quincy Jones as conductor, the band was Mr. Gruntz's.
Born in Basel on June 24, 1932, Mr. Gruntz studied music in his hometown and in Zurich. He worked with the Swiss trumpeter Flavio Ambrosetti, traveled to the United States in 1958 to play at the Newport Jazz Festival with the International Youth Band, and over the next decade often worked with American musicians who came to visit or live in Europe, including Mr. Konitz, the saxophonists Dexter Gordon and Phil Woods, the trumpeter Don Cherry and the drummer Kenny Clarke.
He was stylistically wide-ranging from the start: A few years after composing the straight postbop soundtrack music for the 1960 Swiss film "Mental Cruelty," he played the harpsichord on the two-album series "Jazz Goes Baroque."
Mr. Gruntz was an ambitious multidisciplinary collaborator. He wrote the words and music to jazz oratorios and collaborated on jazz operas with Amiri Baraka ("Money: A Jazz Opera," first performed in 1982 at LaMama E.T.C. in New York City) and Allen Ginsberg ("Cosmopolitan Greetings," directed by Robert Wilson for the Hamburg State Opera in 1988). At the 1991 Chicago Jazz Festival he presented "Chicago Cantata," a work combining gospel choirs, blues musicians and two jazz soloists: Von Freeman on tenor saxophone and Lester Bowie on trumpet.
For 16 years he was the chief musical director at Zurich's State Theater, and from 1972 to 1994 he was artistic director of Jazzfest Berlin, one of Europe's bigger jazz festivals.
But his main project was the Concert Jazz Band, which he founded along with Flavio Ambrosetti; his son Franco Ambrosetti, also a trumpeter; and the Swiss drummer Daniel Humair. The band made more than 20 albums and was a mainstay at European jazz festivals and sometimes American ones. It also performed in China, Egypt and Russia.
His last recording session was in November in New York. He composed, arranged and conducted the music, but did not play piano.
In addition to his son, Mr. Gruntz is survived by his wife of 57 years, Lilly Gruntz-Roth; his daughter, Philene Pohlhausen; and a grandson.