Edward Michael Harrington Jr. (February 24, 1928 – July 31, 1989) was an American democratic socialist. As a writer, he was best known as the author of The Other America (1962). Harrington was also a political activist, theorist, professor of political science, and radio commentator. In 1982, he was a founding member of the Democratic Socialists of America, and its most influential early leader.

Harrington was born in St. Louis, Missouri, on February 24, 1928, to an Irish-American family. He attended St. Roch Catholic School and St. Louis University High School, where he was a classmate (class of 1944) of Thomas Anthony Dooley III. He attended the College of the Holy Cross, where he obtained his B.A., and later graduated from the University of Chicago with an M.A. in English literature. Harrington also attended Yale Law School, dropping out after one year.

As a young man, Harrington was interested in both leftist politics and Catholicism. He joined Dorothy Day's Catholic Worker Movement, a communal movement that stressed social justice and nonviolence. Harrington enjoyed arguing about culture and politics, and his Jesuit education had made him a good debater and rhetorician.

Harrington was an editor of the newspaper Catholic Worker from 1951 to 1953, but he soon became disillusioned with religion. Although he always retained a certain affection for Catholic culture, he ultimately became an atheist.

Harrington's estrangement from religion was accompanied by an increasing interest in Marxism and secular socialism. After leaving The Catholic Worker, Harrington became a member of the Independent Socialist League (ISL), a small organization associated with the former Trotskyist activist Max Shachtman. Harrington and Shachtman believed that socialism, which they believed implied a just and fully democratic society, could not be realized by authoritarian communism, and were fiercely critical of the "bureaucratic collectivist" states in Eastern Europe and elsewhere.

In 1955, Harrington was placed on the FBI Index, whose master list contained more than 10 million names in 1939. From the 1950s through to the 1970s, FBI director J. Edgar Hoover added an untold number of names of U.S. activists he considered "dangerous characters", to be placed in detention camps in case of a national emergency. Later, Harrington was added to the master list of Nixon political opponents.

After Norman Thomas's Socialist Party absorbed Shachtman's ISL in 1957, Harrington endorsed Shachtman's strategy of working as part of the Democratic Party rather than sponsoring candidates as Socialists. Although Harrington identified personally with the socialism of Thomas and Eugene Debs, the most consistent thread running through his life and his work was a "left wing of the possible within the Democratic Party."

Harrington served as the first editor of New America, the official weekly newspaper of the Socialist Party-Social Democratic Federation, founded in October 1960. In 1962, he published The Other America: Poverty in the United States, a book that has been credited with sparking John F. Kennedy's and Lyndon Johnson's War on Poverty. For The Other America, Harrington was awarded a George Polk Award and The Sidney Award. He became a widely read intellectual and political writer, in 1972 publishing a second bestseller, Socialism. His voluminous writings included 14 other books and scores of articles, published in such journals as Commonweal, Partisan Review, The New Republic, Commentary, and The Nation.