Feldman's works are characterized by notational innovations that he developed to create his characteristic sound: rhythms that seem to be free and floating, pitch shadings that seem softly unfocused, a generally quiet and slowly evolving music, and recurring asymmetric patterns.

[4] Feldman's first composition teachers were Wallingford Riegger, one of the first American followers of Arnold Schoenberg, and Stefan Wolpe, a German-born Jewish composer who had studied under Franz Schreker and Anton Webern.

With Cage's encouragement, Feldman began to write pieces that had no relation to compositional systems of the past, such as traditional tonal harmony or serialism.

Feldman's experiments with notation and indeterminacy inspired Cage to write pieces like Music of Changes, where the notes to be played are determined by consulting the I Ching.

[citation needed] Through Cage, Feldman met many other prominent figures in the New York arts scene, among them Jackson Pollock, Philip Guston and Frank O'Hara.

[12] The first piece of this new period was a short, 55-measure work, "Madame Press Died Last Week at Ninety", dedicated to his childhood piano teacher.

[citation needed] Late in his career, Feldman produced a number of very long works, rarely shorter than half an hour and often much longer.