Some of the most passionate social and political activists in the US have turned to literary journalism to persuade others to adopt and to act upon their heartfelt convictions. This chapter explores the link between literary journalism and social activism, focusing primarily on Jacob Riis, who practiced a literary journalism of advocacy (in both text and pictures) in the late nineteenth and early twentieth centuries, and on Barbara Ehrenreich, who has been writing literary journalism to advance social reform since the 1970s. Both of these writers make literary journalistic techniques and styles central to their activism, a characteristic that binds them across more than a century’s time. The chapter addresses these two journalists’ vision of journalism—its aims and purposes vis-à-vis societal change—and their conception of their roles as journalists/activists. To provide context, this chapter also addresses the work of the environmentalist writer Henry David Thoreau in the mid-nineteenth century and the socialist activist writer John Reed in the World War I era, with brief attention to twentieth-century writer-activists Dorothy Day and Meridel LeSueur. All wrote literary journalism to foment social change, showing a deep-seated sense of moral concern often developed through immersion in firsthand experiences.