This paper analyzes the symbiotic and mutually reinforcing relationship between the anti-American movement and other social movements in democratic South Korea since 1987. Proposing a new typology of anti-Americanism, the paper formulates and develops an argument that the anti-American movement has substantially contributed to the success and survival of South Korea’s social movements. The anti-American movement should not be classified as one of the many social movements active in South Korea; rather, it is a special movement that performs various functions integral to the rise, expansion, unity, and success of social movements in general. The collaboration of the anti-American movement and other social movements is also transforming the character of the anti-American movement itself. The metamorphosis of the anti-American movement into diverse new social movements makes it more sophisticated, accessible, appealing, open, and flexible. Thus transformed, the anti-American movement will likely provide an important source of vitality for civic engagement and make significant contributions to South Korean democracy.