The concept of "camp," as understood in its modern aesthetic sense, wasn't created by a single individual, but its understanding and popularization are heavily attributed to Susan Sontag.
While elements of camp can be traced back further in history, particularly to the flamboyant style and excess associated with figures like King Louis XIV, it was Susan Sontag's 1964 essay, "Notes on 'Camp'," published in Partisan Review, that formalized and defined the modern understanding of camp as an aesthetic sensibility.
Therefore, while not inventing the behaviors or styles that constitute camp, Sontag's essay is crucial in understanding the theory and critical framework surrounding it. Without her, the scattered examples and tendencies would lack cohesion and a named critical identity.