Final answer:
Ornette Coleman is the musician associated with pioneering free jazz, a genre that emphasizes improvisation and breaks away from traditional jazz structures.
Step-by-step explanation:
The musician often associated with pioneering free jazz is Ornette Coleman. Free jazz, an avant-garde and formless genre, challenges traditional jazz through experimentation and deviation from established structures. Ornette Coleman's approach to jazz was characterized by a departure from fixed chord progressions and a focus on improvisation. Emphasizing expression, spontaneity, and exploration, Coleman's music embodied the spirit of free jazz, which diverged significantly from the works of other influential jazz musicians like Louis Armstrong, Charlie Parker, Duke Ellington, and the historical movement outlined by the Harlem Renaissance.