Jacob Riis, the third of fifteen children, was born in Ribe, Denmark, on 3rd May, 1849. He worked as a carpenter in Copenhagen before emigrating to the United States in 1870. Unable to find work, he was often forced to spend the night in police station lodging houses.
Riis did a variety of menial jobs before finding work with a news bureau in New York City in 1873. The following year he was recruited by the South Brooklyn News. In 1877 Riis became a police reporter for the New York Tribune. Aware of what it was like to live in poverty, Riis was determined to use this opportunity to employ his journalistic skills to communicate this to the public. He constantly argued that the "poor were the victims rather than the makers of their fate".
In 1888 Riis was employed as a photo-journalist by the New York Evening Sun. Riis was among the first photographers to use flash powder, which enabled him to photograph interiors and exteriors of the slums at night. He also became associated with what later became known as muckraking journalism.
In December, 1889, an account of city life, illustrated by photographs, appeared in Scribner's Magazine. This created a great deal of interest and the following year, a full-length version, How the Other Half Lives, was published. The book was seen by Theodore Roosevelt, the New York Police Commissioner, and he had the city police lodging houses that were featured in the book closed down.
Harold Evans, the author of The American Century: People, Power and Politics (1998) has pointed out: "Jacob Riis estimated that Dickensian London had 175,816 people living on every square mile of its worst slums but New York's Lower East Side by the nineties in contrast, had about 290,000 per square mile, making it perhaps the worst slum in the history of the Western world.... He records a tenement block with 1,324 Italian immigrants living in a total of 132 rooms. In one 12-by-12-foot room he found five families, 20 people, with two beds between them. One third of the entire city population - about 1.2 million - lived in 43,000 tenement houses like these, without running water or indoor flush toilets... Some 40 percent of them had tuberculosis. One third of all their babies died before their first birthday."
Over the next twenty-five years Jacob Riis wrote and lectured on the problems of the poor. This included magic lantern shows and one observer noted that "his viewers moaned, shuddered, fainted and even talked to the photographs he projected, reacting to the slides not as images but as a virtual reality that transported the New York slum world directly into the lecture hall."
The work of Riis inspired Lincoln Steffens, the man considered to be the "godfather" of investigative journalism argued in Autobiography (1931): "He (Riis) not only got the news; he cared about the news. He hated passionately all tyrannies, abuses, miseries, and he fought them. He was a terror to the officials and landlords responsible, as he saw it, for the desperate condition of the tenements where the poor lived. He had exposed them in articles, books, and public speeches, and with results. All the philanthropists in town knew and backed Riis, who was able then, as a reformer and a reporter, too, to force the appointment of a Tenement House Commission that he gently led and fiercely drove to an investigation and a report which - followed up by this terrible reporter-resulted in the wiping out of whole blocks of rookeries, the making of small parks, and the regulation of the tenements."
Riis also wrote over a dozen books including Children of the Poor (1892), Out of Mulberry Street (1898), an autobiography, The Making of An American (1901), The Battle With the Slum (1902), and Children of the Tenement (1903).