The city of Chicago is itself a character in Carl Sandburg's volume Chicago Poems. The poem "Chicago" describes the city in the following way: "Stormy, husky, brawling, / City of the Big Shoulders." Chicago is personified, or made into a person who is strong and ready to fight. Chicago is described in this poem as brutal and dishonest, but the city is also resilient, inventive, and proud. The poet describes Chicago as laughing, the way a young, untried person laughs who has yet to prove himself or herself. In this poem, the poet refers to the city as "you," and he speaks to Chicago as if it were a fellow conversationalist. Chicago is a proud upstart with brawn and muscle.

The poet himself is also a character in these poems. For example, in the poem "The Harbor," he describes weaving his way through the ugly walls of the city in which women are peering with "hunger-deep eyes." He makes his way into a view of the refreshingly blue lake above which gulls cry. He is a character who finds his own way in the city of Chicago.

In addition, the poems are populated by the working people of Chicago—people such as the teamster in the poem "The Teamster's Farewell" who bids goodbye to the city he loves when he is on his way to the penitentiary. There are characters such as "Mamie" in the poem of the same name. She dreams of something greater in the small Indiana town where she's from, and she follows her dreams to Chicago, where she works in a basement store and still dreams of something greater. In addition to these types of named characters, the mass of people in Chicago is also a character. For example, in the poem "Skyscraper," masses of people crowd in and out of the skyscraper, giving the building its life and dreams. These are mainly the working people of the city—people such as the workers who constructed the skyscraper, the stenographers who work inside the building, and the people who clean the building each day.