Foreign intern training is a typical case study for investigating personnel exchanges among socialist bloc countries during the Cold War. Receiving and training North Korean interns was the beginning of China’s foreign intern training program. Additionally, China’s training of foreign interns in the Cold War is an ideal case study for Chinese scholars who adopt transnational history approaches. In accordance with transnational history research approaches, studying the North Korean interns from the perspective of “bottom-up politics” contributes to the reconstruction of the history of Sino–North Korean relations. On the basis of primary documentation from Shanghai Municipal Archive as well as documents from the Chinese Foreign Ministry Archive and Hebei Provincial Archive, this article narrates the history of North Korea’s selecting of interns and China’s training of them in Shanghai from 1953 to 1967. The article reconstructs the daily interaction of the North Korean interns with their Chinese hosts. It highlights some of the common features in the evolution of the relations between the Chinese Communist Party (CCP) and the Korean Workers’ Party (KWP), and between the People’s Republic of China and the Democratic People’s Republic of Korea. From a longer and broader historical perspective, the article concludes that intern training programs usually became the victim of deteriorating bilateral relations. Thus, technical training served as an accurate barometer of the CCP–KWP relationship. It failed to be the driving force for promoting Sino–North Korean state-to-state relations.