The body is the core of our internal and external experiences. The existential and phenomenological complexity of the body is presented by Sartre in Being and Nothingness, and his multidimensional approach to corporeality has sometimes been interpreted as a failed attempt to overcome Cartesian ontology and the mind-body problem. This paper aims to reconsider the Sartrean approach not as a return of Cartesian dualism, but as an investigation of the irreducible dynamics of corporeality, which not only overcome Cartesianism but also offer an original answer compared to other phenomenological approaches. First, I analyse the intrinsic relationship between consciousness, the body, and the world in Sartre’s phenomenological analysis. Then, I present the three existential dimensions of corporeality, the body-for-itself, the body-for-others, and the body-for-itself-for-others, and argue that Sartre aims to stress the «tensional integrity» of bodily consciousness, through its paradoxical and multidimensional nature. This many-layered complexity is far from proposing a rigid dualism between the subjective and the objective body; rather, it represents a dynamic and dialectical process of attractions and oppositions. Lastly, I argue that the phenomenal richness of bodily experience developed by Sartre can offer a non-reductive interpretation of body for contemporary cognitive science.