To support his project, Sheldon held jobs in various capacities throughout North Carolina. In the 1970s Sheldon worked at the Cone Mills-Eno textile plant in an attempt to organize workers into a union. He was fired for disseminating pro-union materials while on the floor of the plant. In the 1980s, Sheldon was employed as a nurse. In the late 1980s, Internationalist Books became a successful enough enterprise, such that Sheldon was able to quit his "day jobs" to focus on managing the bookstore. In 1986, the Internationalist became the center for organizing opposition to the Shearon Harris Nuclear Plant. In January 1991, the Internationalist organized opposition to the Gulf War, with Sheldon making appearances on WRAL-TV to speak against the war.