Nowadays we are encountering many different ways in which designers are telling the stories of social innovation. This phenomena makes us wonder how we can start a reflection on the philosophical value of storytelling, and see whether this can be somehow helpful in feeding our practice as designer. Amongst the many philosophers who have been working on the idea of storytelling, we let ourselves be inspired by the work of the German philosopher Hannah Arendt. She believes that storytelling is in essence the act to recognise the potentiality that is hiding behind the mainstream, and be able to read this potentiality, to translate it, to tell its story. This act of telling stories is what Hannah Arendt recognises as the real political action that opens up the idea of public space, where everybody is invited to take part in the discussion of which the decisions upon the polis, on the common realm, are taken together. This act of telling stories brings together the act of telling and the one of making, as it used to be in the Greek world poiseis. Storytelling is to Arendt poetry: an action that takes place through words. Through storytelling the potentialities of the past, what was already there and was not manifested yet because not belonging to the mainstream, finally has the chance to become actual, to show its pregnancy.