Babbitt was born in Philadelphia, Pennsylvania, but his family moved to Jackson, Mississippi at an early age. He studied violin and later clarinet and saxophone as a child. Early in his life he showed ability in jazz and popular music.
Babbitt's father was a mathematician, and it was mathematics that Babbitt intended to study when he entered the University of Pennsylvania in 1931. However, he soon left, and went to New York University to study music instead. There he became interested in the music of the composers of the Second Viennese School, and went on to write a number of articles on twelve tone music including the first description of combinatoriality and a serial "time-point" technique. After receiving his degree in 1935, he studied under Roger Sessions, first privately, later at Princeton University.
In 1947, Babbitt wrote his Three Compositions for Piano, which are thought to be the earliest examples of total serialisation in music, pre-dating Olivier Messiaen's Mode de valeurs et d'intensitÚs by two years, and Pierre Boulez' Polyphonie X by five.
Babbitt later became interested in electronic music. He was hired by RCA as consultant composer to work with their RCA Mark II synthesiser, and in 1961 produced his Music for Synthesiser. Unlike many composers who saw electronic instruments as a way of producing new timbres, Babbitt was more interested in the degree of precision he could get in performances by synthesisers, impossible with human performers.
Babbitt continued to write both electronic music, and music for conventional musical instruments, sometimes combining the two. Philomel (1964), for example, written in collaboration with the poet John Hollander, is for magnetic tape and musical ensemble. Since his experiences with electronic synthesisers, his pieces for conventional instruments have sometimes been so complex as to be almost unplayable.