Although Jean-Paul Sartre adopted the term "existentialism" for his own philosophy in the 1940s, Marcel's thought has been described as "almost diametrically opposed" to that of Sartre.
Meskipun Jean-Paul Sartre mengadopsi istilah "eksistensialisme" untuk filsafatnya sendiri pada tahun 1940an, pemikiran Marcel sering digambarkan "berlawanan hampir sepenuhnya" dengan penggunaan Sartre.