Richard John Dufallo was born on January 30, 1933, in Whiting, Indiana. His family moved to Chicago when he was twelve years old, and Dufallo showed early aptitude on the clarinet, doubling on saxophone. He studied at the American Conservatory of Music in Chicago from 1950 to 1953, and served in the U.S. Navy from 1953 until 1955. He then earned bachelor's and master's degrees at the University of California at Los Angeles, studying with Lukas Foss and playing in Foss' Improvisation Chamber Ensemble.
From 1963 until 1967, Dufallo served as associate conductor of the Buffalo Philharmonic, where Lukas Foss was music director. Dufallo also joined the faculty of the State University of New York at Buffalo, and studied under William Steinberg at a New York Philharmonic seminar for conductors. Leonard Bernstein appointed him as an assistant conductor of the New York Philhamonic in 1965, and he served in this capacity until 1975. During this time, he studied with Pierre Boulez in 1969, and became artistic director the Conference on Contemporary Music at the Aspen Festival, also teaching at the Juilliard School.
Dufallo made his European debut in 1970, and enjoyed a long association with several ensembles in the Netherlands, including the Dutch Radio Philharmonic, and the Gelders Orchestra of Arnhem, where he became artistic director in 1980. In Europe, Dufallo advocated for the performance of works by American composers, giving the first European performances of works by Charles Ives, Carl Ruggles, Jacob Druckman, and Elliott Carter, among others. More broadly, as an advocate for contemporary music, he also premiered works by Karlheinz Stockhausen, Sir Peter Maxwell Davies, and Krzystof Penderecki.
In 1989, Dufallo published the book Trackings: Composers Speak with Richard Dufallo, assembled from extensive interviews which Dufallo conducted with numerous contemporary composers, many of whom Dufallo had worked with, having gained a detailed knowledge of their compositions by conducting them. Those composers include Lukas Foss, Karlheinz Stockhausen, David Del Tredici, and Karl Schat.
Richard Dufallo was married to Pamela Mia Paul, a pianist, faculty member of the University of North Texas College of Music, and daughter of composer Charles Paul. Dufallo died in Denton, Texas on June 16, 2000.