After World War II, Kennedy worked as a journalist for the liberal newspaper "PM" and as a part-time correspondent for publications such as the "New York Post" and "The Nation". He also fed information about discrimination to columnist Drew Pearson. His stories appeared in newspapers and magazines such as the "New York Post" for which he was for a time Southern correspondent, and he fed information about discrimination to columnist. To bring the effects of Jim Crow in the South to public awareness, he authored a number of exposés of the Klan and the racist Jim Crow system over the course of his life, including "Southern Exposure" (1946), "Jim Crow Guide to the USA" (1959), and "After Appomattox: How the South Won the War" (1995). During the 1950s, Kennedy's books, considered too incendiary to be published in the US, were published in France by the existentialist philosopher Jean-Paul Sartre and subsequently translated into other languages. Kennedy coined the term "Frown Power", when he started a campaign with that name in the 1940s, which simply encouraged people to pointedly frown when they heard bigoted speech.