At age ten, moved with mother to Pennsylvania after parents' separation; neighbor Oscar Hammerstein II served as mentor
Wrote first amateur musical, "By George" while still in boarding school
Wrote for the CBS TV series, "Topper"
Wrote first musical score, "Saturday Night"; show was optioned for production, but the producer died before funding had been raised; project was shelved until a 1997 production at London's Bridewell Theatre; received a professional recording in 1998
First professional stage work, composed incidental music for "Girls of Summer"
Wrote lyrics to Broadway show, "West Side Story"; adapted into a film in 1961
Only original teleplay produced, "In an Early Winter"
Contributed to the CBS special "The Fabulous 50s"
Wrote lyrics and music for "A Funny Thing Happened on the Way to the Forum"; adapted into a film in 1966
Composed and wrote lyrics for first TV score, "Evening Primrose"
First collaboration with Harold Prince as director, "Company"; recording of the cast album was the subject of D. A. Pennebaker's documentary
Wrote the score for the cult musical "Follies"
With Anthony Perkins, co-wrote first original screenplay, "The Last of Sheila"; directed by Herbert Ross
TV acting debut in a PBS' production of "June Moon"
Composed first original film score, "Stavisky"
First stage revue based on his work, "Side by Side by Sondheim"
Wrote song "I Never Do Anything Twice/The Madam's Song" for the Herbert Ross-directed film "The Seven Per Cent Solution"
Wrote new songs for the Harold Prince directed film adaption of the Tony-winning musical, "A Little Night Music"
Wrote the music and lyrics for the Broadway musical, "Sweeney Todd"; final collaboration with book writer Hugh Wheeler
Last collaboration to date with Prince, "Merrily We Roll Along"
Contributed to the score of Warren Beatty's "Reds"
Stage revue, "Marry Me a Little"; included songs cut from various productions; show assembled by Craig Lucas
First TV adaption of one of his musicals, "Sweeney Todd"; aired on The Entertainment Channel; later rebroadcast on PBS
First collaboration with James Lapine, "Sunday in the Park With George"; received Pulitzer Prize in Drama
An all-star concert version of "Follies" was performed at Lincoln Center; filmed for broadcast on PBS
"Sunday in the Park With George" broadcast on PBS with the original cast
A revised version of "Follies" opened in London's West End with Diana Rigg, Julia McKenzie and Daniel Massey
Second collaboration with Lapine, "Into the Woods"
Provided the song score for Warren Beatty's feature "Dick Tracy"; won Oscar for song "Sooner or Later"
The City Opera production of "A Little Night Music" aired on PBS' "Live From Lincoln Center"
Appointed first visiting professor of drama and musical theater at Oxford University
The controversial musical "Assassins" opened; main characters were all successful or would-be presidental assassins
Second stage revue of Sondheim work, "Putting It Together"; show marked the return to the stage of Julie Andrews
Was subject of tribute, "Sondheim: A Celebration at Carnegie Hall"; filmed for TV and aired in 1993 on PBS
Third collaboration with James Lapine, "Passion"; based on Ettore Scola's 1981 film "Passione d'amore"
Made debut as playwright, co-authoring "Getting Away With Murder" with George Furth
Wrote several songs for Mike Nichols' feature "The Bird Cage"; most songs not used in the final cut
Yet another revised version of "Follies" staged at the Paper Mill Playhouse in New Jersey
Revised version of Off-Broadway revue "Putting It Together" starring Carol Burnett opened in L.A.; production re-staged (with some cast changes) on Broadway
Workshop version of "Wise Guys" staged; directed by Sam Mendes; never transfer to Broadway
Off-Broadway premiere of "Saturday Night" at the Second Stage Theatre
First Broadway revival of "Follies" produced under auspices of Roundabout Theater
The Kennedy Center devoted entire season to works
Broadway revival of "Into the Woods"
Tony award winning Broadway revival of Sondheim's "Assassins"
Broadway revival of "Sunday in the Park with George"
Earned two Grammy nominations for Best Musical Show Album as the lyricist for "A Little Night Music" and "Sondheim On Sondheim"