This dissertation argues for the historical importance of two understudied artists of the 1960s, and beyond: Kate Millett, an American radical feminist, and Jean-Jacques Lebel, a French anti-Algerian War activist who went on to lead in the student/worker movement of Paris 1968. Both are artists, writers, and theorists who critiqued prevailing mores and celebrated a morality of libertine sexuality. This study explores their multiple activities and the ways in which each linked cultural and political avant-gardes. In doing so it sheds light on the contributions of experimental artists and their international and interdisciplinary circles to broader social developments. This dissertation has a tripartite structure. Firstly, it is grounded on close examination of the art and writings of Millett and Lebel. Secondly, it presents a theoretical argument for the convergence of three tendencies that shaped politicized art in the 1960s: an insubordination inspired by Dada, an ethics of committed action reflecting philosophical Existentialism, and a utopic belief in the revolutionary potential of liberated sexuality. Thirdly, it gives a historical reading of the transnational cultural circles in which Lebel and Millett worked in order to consider the evolution of avant-garde intermedia, art that operates between traditional media. This dissertation concludes that, despite differences in perspective regarding gender, sexuality, and the means that these artists use to radicalize their audiences, Millett and Lebel had certain critical similarities that made them icons of the 1960s: artistic backgrounds, shared morality of dissent, and individual lives of committed acts. This theoretical and historical work contributes to the history of experimental art, especially of Fluxus and happenings, and enriches understanding of the foundational practices of much contemporary art as well as scholarship on the interrelationship of culture and politics.