The advent of post-Cold War order, growing economic interdependence and dense social and cultural networks have greatly facilitated South Korea's bilateral ties with China and Japan since the early 1990s; however, disputes over the history and territory have recently strained such ties. Whereas Japan's renewed territorial claim over Dokdo Island, its distortion of history textbooks and Koizumi's tribute to the Yasukuni Shrine dealt a critical blow to Seoul–Tokyo relations, China's Northeast Project, which claims Korea's ancient kingdom of Goguryeo as a Chinese peripheral local government, provoked widespread anti-Chinese sentiments in South Korea. Nevertheless, South Korea's nationalist responses were not uniform. Seoul responded to Tokyo in a much tougher manner with profound diplomatic implications, whereas public outcry over China did not escalate into any specific retaliatory actions. This article argues that such variation can be explained by the dynamic interplay of issue–character, domestic political terrain involving public opinion and leadership perception and feedback from political leadership in China and Japan.