Considering the pedigree on display for this movie, the screenwriter didn't have to do very much. With Steven Sondheim and Leonard Bernstein handling the musical numbers, the only thing really left to do was fill in the blanks. Nevertheless, this was a high-end production and you didn't want to trust any aspect of it to some hack.
Enter Ernest Lehman, a native New Yorker from a wealthy family whose fortunes hit the skids (along with everyone else's) when the Great Depression hit. To make ends meet, he started writing for publicity firms, promoting famous people in gossip columns. It didn't sit well with him, but Hollywood soon beckoned.
When he tried his hand at screenwriting, magic happened.
Magic Typewriter? Or Just an Awesome Screenwriter?
Lehman's first film was called Executive Suite, and we don't see much of it today. But it was a big hit, and the studio asked him to co-write another one with director Billy Wilder. It was called Sabrina. It starred Audrey Hepburn, Humphrey Bogart and William Holden, and it was an instant classic.
From there, things happened fast. Adaptation was his specialty. He transposed the stage musical The King and I into movie form in 1956, and it became another classic. Lehman put his experiences with the gossip columns to work with a movie called Sweet Smell of Success in 1958. It became a—you guessed it— classic. Alfred Hitchcock tapped him to write the screenplay for North by Northwest (his only original screenplay), and it became a classic.
Detecting a pattern here? Our man had the skillz to pay the bills and in the process helped bring a heaping fistful of immortal films to life.
Classic Movies: One of Many
West Side Story kept Lehman's streak going. Sure, he already had the already hugely successful stage musical to work with, and with Sondheim and Bernstein working on the songs, he didn't have to worry much. (Lots of movies made back then were based on novels or plays.) But he did contribute some terrific sequences, and some of the most important changes from the stage play can likely be credited to Lehman.
For example, he moved the upbeat "Gee Officer Krupke" song earlier in the film, before Riff is killed, so the happy vibes feel more in keeping with the overall story. The intense, downbeat "Cool" comes after Riff dies, when his gang buddies are definitely in an anxious mood.
Lehman didn't slow down when he was finished with West Side Story, writing movies like The Sound of Music, Who's Afraid of Virginia Woolf?, Hello Dolly and another Hitchcock flick just for good measure.
It's a staggering legacy. And amazingly enough, he never actually won an Oscar for any of them: nominated five times and walking away empty-handed each time. Even West Side Story, which tore through the Academy's little trophy ceremony like a buzz saw, didn't give Lehman his Oscar. (It went to Abby Mann, who wrote Judgement at Nuremburg, and that's a great movie too, so we won't squawk too loud.) The Academy gave him an honorary Oscar in 2001, just four years before his death, so they at least acknowledged the oversight.
Luckily, he didn't need a shiny statue to validate his work. Once glance at any of his films and you can see how good he was.