* BreakthroughHit: Despite Sondheim disowning later on, this musical put him on the map as one of the most well-known writers on Broadway.
* CreatorBacklash: Stephen Sondheim doesn't think very highly of the lyrics he wrote for this. Some songs sound as simplistic as something a real New York teen would improvise ("Maria!/I've just met a girl named Maria/And suddenly that name/Will never be the same/To me.") while others sound too complex ("I feel pretty/Oh so pretty/I feel pretty and witty and gay!/And I pity/Any girl who isn't me today.").
* EnforcedMethodActing: While filming the movie, the actors playing the Jets and the Sharks were roomed separately in order to heighten the tension between the two groups.
** Averted in "Anita's Rape Scene." In that scene, the actress playing Anita, Rita Moreno, was reduced to tears as a result of shooting that scene, as it brought back memories of when she was raped as a child. When she started crying, the actors playing the Jets immediately stopped what they were doing and began comforting her, while pointing out that the viewers were going to hate them for what they were doing.
* FakeNationality: In the film, Maria is played by NatalieWood, who was a Russian-American. And then there's the Greco-American George Chakiris as Bernardo.
* TroubledProduction: The director, with his background in stage, shot and re-shot until the film was over $1,000,000 over budget and six months behind schedule. He was fired, and his co-director had to finish the film alone.
* WhatCouldHaveBeen:
** The first draft, ''East Side Story'', starred a couple with conflicting religions.
** An alternate opening showed the Jets in a clubhouse, fantasizing about going to the moon.
** Maria would have sung about the murderous power of hate, instead of making a dramatic speech.
** Early casting choices for the movie's Tony included Music/ElvisPresley and Creator/WarrenBeatty. Ironically, both of them had real-life affairs with NatalieWood.