Drawing on Heidegger’s understanding of the temporal order of human existence and the primacy of ecstasy of the future for its constitution, the question presented here is the particularity of Heidegger’s understanding of the existential potentiality and existential self. In a modal-theoretical sense, Heidegger marks a significant departure from traditional metaphysical concepts, determining existential possibility as something constituted in relation to a certain yet unforeseeable possibility of the end of one’s own existence. These considerations lead to the thesis of the possibility of a narrative expression of authentic existence by claiming an ontological equivalence between existential and narrative potentiality.