Babbitt died Saturday of natural causes at University Medical Center at Princeton in New Jersey, the university announced.
In the 1950s, RCA hired Babbitt as a consultant as it was developing the Mark II synthesizer. He became a founder and director of the Columbia-Princeton Electronic Music Center, where the synthesizer was installed.
He blended electronic music with vocal performances in compositions such as "Vision and Prayer" and "Philomel" in the 1960s and "Reflections" in the 1970s.
"Milton has managed to do something that almost no other composer, except maybe Bach, has done to such an extent: the technique is the content of the music and the content of the music is the technique, a perfect symbiosis," composer and conductor Gunther Schuller told the Boston Globe in 2005. "The way he writes it is the way it has to come out."
Princeton awarded Babbitt a doctorate in 1992, 46 years after his dissertation on the 12-tone system of modern composers was rejected.
"His dissertation was so far ahead of its time it couldn't be properly evaluated at the time," Theodore Ziolkowski, a close friend of Babbitt's and then-dean of Princeton's graduate school, said in 1992.
In the mid-1940s, the music department awarded doctorates for historical musicology, not composing.
Ziolkowski said faculty members weren't satisfied with the honorary doctorate that Princeton had awarded Babbitt in 1991.
"We thought it wasn't right that such a distinguished composer and music theoretician who has contributed so much to music in this country should not have the degree he had earned," Ziolkowski said.
Born May 10, 1916, in Philadelphia, Babbitt grew up in Jackson, Miss., and earned degrees from Princeton and New York University. He joined Princeton's faculty in 1938 and became a professor emeritus of music there in 1984.
Paul Lansky, a composer and Princeton University colleague who was once a student of Babbitt's, said Babbitt felt strongly that music should be "an advanced subject that's open to study and contemplation the way philosophy or mathematics is. ... It was something he stood by his whole life."
Babbitt received a special Pulitzer citation for his life's work in 1982, won a MacArthur Foundation grant in 1986, and the Gold Medal of the American Academy and Institute of Arts and Letters in 1988.
He told The Times in 1986: "Even so-called popular composers don't really care what an audience likes. In the end you write for yourself."
Babbitt is survived by his daughter, Betty Ann Duggan, and two grandchildren, Princeton said.