Final answer:
Ezra Pound, a central figure of the Modernist movement, famously urged poets and artists to "Make it new!" He promoted this mantra through his own poetry and by supporting other Modernist writers, contributing to a profound shift in artistic expression during the 20th century.
Step-by-step explanation:
The modernist poet who famously proclaimed "Make it new!" was Ezra Pound. As a leading figure in the Modernist movement, Pound championed a break with traditional forms and encouraged experimentation, epitomized by the free-form approaches of Low Modernism. He influenced literature not only through his own poetry but also by supporting and editing the works of others, fostering a generation of Modernist writers.
Marianne Moore, part of the Modernist wave, often utilized plain language and concrete images to express her themes. Moore, unlike Pound, navigated a unique path within Modernism, using detailed observations and precise language within her lyric poetry to convey vivid, almost sculptural, poetic images.
In term of impact, Pound's directive to "Make it new!" reverberated through various artistic expressions beyond poetry, including music, painting, and literature, encouraging artists and writers to represent the complexities of contemporary life in innovative and unorthodox ways, thereby forging a distinct break from the past.