Il suo primo incontro con la musica avvenne quand'era bambino, studiando prima violino e successivamente il clarinetto e il sassofono. Nel 1931, Babbitt iniziò anche lo studio della matematica presso l'Università della Pennsylvania per poi trasferirsi a New York. Dopo la laurea, si dedicò alla composizione con Roger Sessions. Durante la Seconda guerra mondiale ha lavorato come professore di matematica all'Università di Princeton. Dal 1950 ha partecipato allo sviluppo del primo sintetizzatore. Nel 1959 fu uno dei fondatori del Columbia-Princeton Electronic Music Studio. Ha insegnato in varie università, da ultima la Juilliard School of Music, come professore di composizione. Per le sue realizzazioni in campo seriale ed elettronico ha ricevuto il Premio Pulitzer1982 per la composizione e, nel 1995, il SEAMUS Lifetime Achievement Award.
Opere
Primo periodo
1935 Generatrix for orchestra (incompiuto)
1939-41 String Trio
1940 Composition for String Orchestra (incompiuto)
1941 Symphony (incompiuto)
1941 Music for the Mass I for mixed chorus
1942 Music for the Mass II for mixed chorus
1946 Fabulous Voyage (musical, libretto: Richard Koch)
1946 Three Theatrical Songs for voice and piano
1947 Three Compositions for Piano
1948 Composition for Four Instruments
1948 String Quartet No. 1 (withdrawn)
1948; 54 Composition for Twelve Instruments
1949 Film Music for Into the Good Ground (withdrawn)
1950 Composition for Viola and Piano
1951 The Widow's Lament in Springtime for soprano and piano
1951 Du for soprano and piano
1953 Woodwind Quartet
1954 String Quartet No. 2
1954 Vision and Prayer for soprano and piano
1955 Two Sonnets for baritone, clarinet, viola, and cello
1956 Duet for piano
1956 Semi-Simple Variations for piano
1957 All Set for alto sax, tenor sax, trp, trb, cb, pno, vib, percussion
1957 Partitions for piano
1960 Sounds and Words for soprano and piano
1960 Composition for Tenor and Six Instruments
1961 Composition for Synthesizer
1961 Vision and Prayer for soprano and synthesized tape
Secondo periodo
1964 Philomel for soprano, recorded soprano, synthesized tape
1964 Ensembles for Synthesizer
1965 Relata I for orchestra
1966 Post-Partitions for piano
1966 Sextets for violin and piano
1967 Correspondences for string orchestra and synthesized tape
1968 Relata II for orchestra
1968-69 Four Canons for SA
1969 Phonemena for soprano and piano
1970 String Quartet No. 3
1970 String Quartet No. 4
1971 Occasional Variations for synthesized tape
1972 Tableaux for piano
1974 Arie Da Capo for five instrumentalists
1975 Reflections for piano and synthesized tape
1975 Phonemena for soprano and synthesized tape
1976 Concerti for violin, small orchestra, synthesized tape
1977 A Solo Requiem for soprano and two pianos
1977 Minute Waltz (or 3/4 - 1/8) for piano
1977 Playing for Time for piano
1978 My Ends Are My Beginnings for solo clarinetist
1978 My Complements to Roger for piano
1978 More Phonemena for twelve-part chorus
1979 An Elizabethan Sextette for six-part women's chorus
1979 Images for saxophonist and synthesized tape
1979 Paraphrases for ten instrumentalists
1980 Dual for cello and piano
Terzo periodo
1981 Ars Combinatoria for small orchestra
1981 Don for four-hand piano
1982 The Head of the Bed for soprano and four instruments
1982 String Quartet No.5
1982 Melismata for solo violin
1982 About Time for piano
1983 Canonical Form for piano
1983 Groupwise for flautist and four instruments
1984 Four Play for four players
1984 It Takes Twelve to Tango for piano
1984 Sheer Pluck (composition for guitar)
1985 Concerto for piano and orchestra
1985 Lagniappe for piano
1986 Transfigured Notes for string orchestra
1986 The Joy of More Sextets for piano and violin
1987 Three Cultivated Choruses for four-part chorus
1987 Fanfare for double brass sextet
1987 Overtime for piano
1987 Souper for speaker and ensemble
1987 Homily for snare drum
1987 Whirled Series for saxophone and piano
1988 In His Own Words for speaker and piano
1988 The Virginal Book for contralto and piano
1988 Beaten Paths for solo marimba
1988 Glosses for Boys' Choir
1988 The Crowded Air for eleven instruments
1989 Consortini for five players
1989 Play It Again, Sam for solo viola
1989 Emblems (Ars Emblematica), for piano
1989 Soli e Duettini for two guitars
1989 Soli e Duettini for flute and guitar
1990 Soli e Duettini for violin and viola
1990 Envoi for four hands, piano
1991 Preludes, Interludes, and Postlude for piano
1991 Four Cavalier Settings for tenor and guitar
1991 Mehr “Du” for soprano, viola and piano
1991 None But The Lonely Flute for solo flute
1992 Septet, But Equal
1992 Counterparts for brass quintet
1993 Around the Horn for solo horn
1993 Quatrains for soprano and two clarinets
1993 Fanfare For All for brass quintet
1993 String Quartet No. 6
1994 Triad for viola, clarinet, and piano
1994 No Longer Very Clear for soprano and four instruments
1994 Tutte Le Corde for piano
1994 Arrivals and Departures for two violins
1994 Accompanied Recitative for soprano sax and piano
1995 Manifold Music for organ
1995 Bicenguinguagenary Fanfare for brass quintet
1995 Quartet for piano and string trio
1996 Quintet for clarinet and string quartet
1996 When Shall We Three Meet Again? for flute, clarinet and vibraphone
1998 Piano Concerto No. 2
1998 The Old Order Changeth for piano
1999 Composition For One Instrument (Celesta)
1999 Allegro Penseroso for piano
1999 Concerto Piccolino for vibraphone
2000 Little Goes a Long Way for violin and piano
2000 Pantuns for soprano and piano
2002 From the Psalter soprano and string orchestra
2002 Now evening after evening for soprano and piano
2003 Swan Song No.1 for flute, oboe, violin, cello, and two guitars
2003 A Waltzer in the House for soprano and vibraphone
2004 Concerti for Orchestra, for James Levine and the Boston Symphony Orchestra
2004 Autobiography of the Eye for soprano and cello