The vocal and dance numbers performed by the characters of musical are its important components. They characterize the characters of the narrative and emphasize its semantic dominance. The process of transferring a theatrical musical to the screen, the conventions of different media conflict with each other, which leads to transformations of the character and related musical numbers. One of the distinguished examples that allows us to trace this process is “West Side Story”, a musical staged on Broadway in 1957, and then filmed twice (in 1961 and 2021). In this article, the transformations of the characters of the three versions of “West Side Story” are shown through the analysis of the musical structure of the texts. Screen adaptations vary the set and sequence of musical numbers, change their internal structure and interface with dramatic dialogues. All this leads to displacements within the character system: the viewer’s focus shifts from the ensemble of heroes to individual figures moving from the periphery of the narrative to its center.