Existentialism was one of the most important philosophical movements in post-World War II Europe. This study shows the consequences of this philosophy in Iran and the influence of its founder, Jean-Paul Sartre. Also, it shows that existentialist discourse in the context of political, cultural and historical developments in the county. The authors argue that initially, Sartre's existentialism was considered as a superficial, imperialist, absurdist and apolitical philosophy in Iran in the 1320s, but gradually Iranian translators and writers with goals of fighting the Shah and joining the cosmopolitan movement turned the philosophy of existentialism into a revolutionary and political ideology. The authors analyze the translation of Sartre's works including, translations, critiques of translations, interviews with translators and textual productions of Iranian writers and intellectuals on existentialism. In the historical context, this study shows how the special circumstances led this generation to adopt a way of action and under the influence of the world anti-colonial revolutions, sought to overthrow the existing system. It separated its ontological and philosophical origins and caused existentialism to be used in Iran before the 1979 revolution not as a philosophy, but more as a political ideology.