Butch Morris, who created a distinctive form of large-ensemble music built on collective improvisation that he single-handedly directed and shaped, died on Tuesday in Brooklyn. He was 65. The cause was cancer, said Kim Smith, his publicist and friend. Mr. Morris, who lived in the East Village, died at the Veterans Affairs Medical Center in Fort Hamilton.

Mr. Morris referred to his method as “conduction,” short for “conducted improvisation.” He defined the word, which he trademarked, as “an improvised duet for ensemble and conductor.”

He would often begin a performance by setting a tempo with his baton and having his musicians develop a theme spontaneously and then seize on the musical ideas he wanted to work with, directing the ensemble with a vocabulary of gestures and signals. An outstretched upward palm, up or down to indicate volume, meant sustain; a U shape formed with thumb and forefinger meant repeat; a finger to the forehead meant to remember a melodic phrase or a rhythm that he would summon again later.

He introduced this concept in 1985 and at first met resistance from musicians who were not willing to learn the vocabulary and respond to the signals; he was often in a position of asking artists to reorient themselves to his imagination and make something new out of familiar materials. But he demanded to be taken seriously, and he was. After 10 years he had made enough recordings to release “Testament,” a well-received 10-disc set of his work. After 20, he had become an internationally admired creative force, presenting conductions at concert halls worldwide and maintaining regular workshops and performances at the East Village spaces Nublu, Lucky Cheng’s and the Stone.

Mr. Morris, who also played cornet, began his career as a jazz musician in Los Angeles. After settling in New York in the early 1980s, he took his place among both the downtown improvising musicians of the Kitchen and the Knitting Factory and the purveyors of multidisciplinary, mixed-media art flourishing in the city.
Lawrence Douglas Morris was born in Long Beach, Calif., on Feb. 10, 1947, and grew up in the Watts neighborhood of Los Angeles. The son of a career Navy man, he played trumpet in school orchestra, and after high school copied big-band arrangements for a Los Angeles music studio. In 1966 he served in the Army, as a medic in Germany, Vietnam and Japan. Once back home, he joined Mr. Tapscott’s big band, a creative and social hub in the Los Angeles experimental-jazz scene.

After studying music at Grove Street College in Oakland, Calif., he briefly moved to New York. In 1976 he left to play and teach music in France and the Netherlands. In 1981 he relocated permanently to New York, not long after his brother Wilber, the bassist through the 1980s and early ’90s in David Murray’s octet, did.