Final answer:
Claude Debussy is recognized as the main exponent of the impressionist movement in music, known for his revolutionary approach to harmony and form which paralleled changes in the visual arts.
Step-by-step explanation:
The primary exponent of the impressionist movement in music, who changed the course of musical development by dissolving traditional rules and conventions into a new language of harmony, rhythm, form, texture, and color, is Claude Debussy. Unlike composers before him, such as Arnold Schoenberg's atonal and twelve-tone experiments, or the traditional scales that dominated the Renaissance period, Debussy's music represents a significant shift towards impressionism in the music world. This shift paralleled changes occurring in other art forms, such as painting, where artists like Paul Cézanne transitioned from Impressionism to Post-Impressionism, influencing subsequent movements like Expressionism. Impressionist composers, notably Debussy, similarly focused on the play of light and color in their compositions, seeking to capture moments and emotions through innovative musical techniques.