Final answer:
Carl Sandburg is the American writer known for winning Pulitzer Prizes for his biography of Abraham Lincoln and his 'Complete Poems,' as well as his famous poem 'Chicago.'
Step-by-step explanation:
The American writer you are referring to is Carl Sandburg, who was born in 1868 in Galesburg, Illinois. He worked for the Chicago Daily News and is renowned for his unique style of poetry and monumental biographical works. Sandburg won Pulitzer Prizes for both his biography of Abraham Lincoln and his Complete Poems.
He was widely recognized for his unrhymed free verse and colloquial style, especially captured in his famous poem "Chicago." This literary icon passed away in 1967, leaving behind a significant impact on American literature.