Oscar DePriest was born in Florence, Alabama, to ex-slaves. He arrived in Chicago in 1889. DePriest worked as a painter and decorator, reportedly on occasion passing for white to get a job. He developed his own contracting business and began participating in community affairs. He began his political career as a precinct secretary, but by 1904 was elected to the Cook County Board of Commissioners.
In 1928 he became the first African American congressman elected to the House of Representatives from a northern state and a national symbol for racial pride. He fought for civil rights but took conservative positions on economic issues and lost his seat to a New Deal Democrat in 1934. He served one more term in the city council at the end of the following decade. De Priest devoted the rest of his years to his real-estate business.