Jacob August Riis was born in Ribe, Denmark on May 3, 1849. The son of a Latin teacher, he drove the rats out of his tenement at the age of 13 and was subsequently trained as a carpenter. He arrived in New York in 1870. For three years he was homeless and found only occasional temporary jobs. Finally he became a police reporter for a New York newspaper. While covering the police beat he met Police Commissioner Theodore Roosevelt and the two became good friends.

After 27 years as a reporter and photographer, he dedicated himself to cleansing the New York slums, and to spread awareness of the plight of New York's immigrant population. He wrote several books including  "How the Other Half Lives." 

Jacob August Riis died of heart disease in Barre, Massachusetts on May 26, 1914. He and his wife Elizabeth had four children.