Who is Stephen Sondheim?
Stephen Sondheim can be considered “the father of the modern American musical”. Sondheim evolved the traditional American musical instead of adopting the more contemporary style of his peers. This fact, along with his body of work including the Tony award winning classics like Sweeney Todd and Into the Woods, make him one of the more important figures in musical theater in the 20th century. 
Why Stephen Sondheim Can Be Considered the Father of the Modern American Musical
If we consider Rodgers and Hammerstein “the fathers of the golden age of the American musical,” then it is Sondheim (at times alone) who carries on their tradition on Broadway from the 50’s until today.
While others staged fluffy pop hits and rock operas for mass audiences, Sondheim blended jazz, opera, and the classics, creating masterworks like A Little Night Music. The title of A Little Night Music is a word play on Mozart’s Eine Kleine Nachtmusik, and the story is based on Ingmar Bergman film Smiles of a Summer Night. The arrangements do the source work justice (to say the least); the vocal parts and orchestration are infamously challenging (like most Sondheim), and the whole thing generally screams “high-popular-art” much in the same way Mozart’s operas do (or in the way Rodgers and Hammerstein’s The Sound of Music does).
Sondheim was taught by greats like Bernstein and Hammerstein, and luckily, he was able to pass on aspects of their art-form to the next generation (something that may not have happened without Sondheim).
This isn’t to say there weren’t other great innovators in American musical theater; it is just to say that none of them carried on and evolved the traditional style in the way Sondheim did. Andrew Lloyd Webber innovated with the rock opera; the more mainstream Stephen Schwartz’s work includes Wicked; Bernstein created one of the best opera’s of the second half of the 20th century, Candide (which is more a throwback to Mozart, or even arguably Brecht and Weill). There are, of course, many more who we haven’t mentioned.
Justifications aside, it is hard to imagine any of those mentioned above failing to honor one of the greatest composers of the 20th century, Stephen Sondheim.
Below we explain who Stephen Sondheim was and why he deserves the title of “Father of the Modern American Musical” in more detail. First, I suggest this video so you can understand Sondheim the musical genius, Sondheim the artist, and Sondheim the teacher (he is full of great insight).
Sondheim teaches Send In The Clowns.
TIP: Send in the Clowns, a simple and hum-able (yet moving) song, was one of Sondheim’s biggest hits, but the true reward of Sondheim is in the numbers, lyrics, and stories not found on popular radio, for instance, the opening number to Company (1971).
Company 02 Company Overture (2006 version with Raúl Esparza as Bobby).
FACT: Stephen Colbert and Neil Patrick Harris starred in a 2011 production of Company. The above version is an equally wonderful version with Raúl Esparza.
TIP: This isn’t the point of this page, but Sondheim is a “musician’s musician”. What that means is he writes complex music and vocal lines that are a joy and challenge to perform. The above overture of Company where the actors play, act, and sing at the same time would be considered very challenging and a feat to be able to perform flawlessly like that.
BUY IT: Stephen Sondheim, when he isn’t busy preserving American theater he is writing books. He has a lot to teach, considering buying Look, I Made a Hat Written by Stephen Sondheim.
Further Justification for Sondheim as the Father of the Contemporary American Musical
If we are looking for greats in the theater we can start with Mozart’s Don Giovanni, the Magic Flute, or the Marriage of Figaro. We can consider Gilbert and Sullivan’s H.M.S. Pinafore or The Mikado. Or, we can start with one of the first great American musicals, Gershwin’s Porgy and Bess, or we can look to “the Golden Age of American musical theater” and consider Rodgers and Hammerstein’s Oklahoma!, Sound of Music, or South Pacific.
If we look at the theater with a lens that considers these greats as forefathers of the American musical, then we are only left with a few modern composers who can really carry the torch from the 50’s until now. Those composers include Leonard Bernstein (who co-wrote West Side Story with Sondheim) and Stephen Sondheim.
West Side Story-Jet Song. West Side Story was co-written by Bernstein (music) and a young Sondheim (lyrics).
We may consider Bernstein and Sondheim to have carried on the tradition of the classics. Others who came after Sondheim, like Stephen Schwartz (Wicked) and Andrew Lloyd Webber (Jesus Christ Superstar and Evita), can be said to be the founders of the “new wave” of American musical (or pioneers of the “rock opera” musical). Rock operas and pop operas include shows like Rent and Book of Mormon, and classics like Rocky Horror and Hair. These were big blockbuster shows with rock and roll, meant to connect with a modern audience.
If we look back to the early 50’s when Sondheim got his start we can find the Sherman Brothers, Irving Berlin, Jerry Herman, Frank Losser, Mel Brooks, and many more. They all make strong candidates, but they didn’t develop the musical for modern times as Sondheim did, although they obviously inspired Sondheim to some extent.
While others made rock operas and palatable shows for a modern audience, Bernstein and Sondheim carried on in the tradition of the Golden Age of the modern musical, which was rooted in jazz and classical music. Others who might deserve the title tended to stop making shows by the 70’s while Sondheim is still alive and contributing to culture today.
With the above justification in mind, and because Sondheim (unlike Bernstein) was prolific as a composer of American musicals, we can fairly easily give the title of “Father of the Modern American Musical” to Stephen Sondheim. This is backed up by this claim and a less detailed justification given in HBO’s new Sondheim documentary Six by Sondheim.
Six by Sondheim (HBO Documentary Films).
Further justification is given by the Tony Awards Sondheim was nominated for and won in 1971 (COMPANY), 1972 (FOLLIES), 1973 (A LITTLE NIGHT MUSIC), 1979 (SWEENEY TODD), 1984 – (SUNDAY IN THE PARK WITH GEORGE, lost to Jerry Herman), 1988 (INTO THE WOODS) 1994 (PASSION), 2008 (a lifetime achievement award presented by Mandy Patinkin). 
Sondheim Tony wins (and one loss) ’71, ’72, ’73, ’79, ’88, ’94, 08.
The Major Works of Stephen Sondheim
Sondheim’s story starts when family friend Oscar Hammerstein teaches a young Sondheim how to write the perfect American Musical and warns Sondheim to use his own voice. He gets a jump-start when the already established Bernstein gives him his first big opportunity writing the lyrics for West Side Story (1957). This is followed by another writing opportunity for the hit Gypsy (1959). Sondheim’s carer takes off starting 1962 with musicals like A Funny Thing Happened on the Way to the Forum, Company, Follies, Sweeney Todd, a Little Night Music, Sunday in the Park with George, and Into the Woods.
Sweeney Todd: The Demon Barber of Fleet Street. Johnny Depp stars in Tim Burton’s version of Sondheim’s Sweeney Todd. A major motion picture was also made for Into the Woods.
Aside from the great works, there are just as many largely forgotten (but often important) minor Sondheim works. Sondheim didn’t always write hits, but he was prolific and has (along with the many greats he worked with) contributed some of the only true “high art” to the American musical theater since Hammerstein’s work in the 50’s and 60’s. For these reasons and others, Sondheim is important.
Below are a few videos to allow you to explore the work of the great Stephen Sondheim further.
Full Interview: Stephen Sondheim.
FACT: Sondheim once said in an interview, where he was paraphrasing advice from Hammerstein, “Write for yourself and you’ll be ahead of 90% of everybody else.” This is one of many great music theory related tips that Sondheim has to share. The only way to find all the great Sondheim-isms is by checking out the videos like the one above, Sondheim’s own work, and the other interviews and documentaries on Sondheim that have been done over the years.
Sondheim at 80 (BBC Proms 2010).
FACT: Sondheim worked with a number of librettists (musical book writers, not necessarily lyricists). The list includes Hal Prince, George Furth, and James Lapine. Other important actors include, but are in no way limited to, Mandy Patinkin, Bernadette Peters, Patti LuPone, Micheal Cerveris, and Angela Lansbury. Aside from them, there are bout 1,000 other actors, writers, musicians, stagehands, and more that we haven’t mentioned. Learn more about Sondheim and his major works at Wikipedia.