This paper examines the young Gramsci`s perspective of theater criticism, focusing on the Theatrical Chronicles he wrote from 1916 to 1920 for Avanti, the Piedmont edition of the Socialist Daily. Although these Chronicles are very fragmentary reviews about particular performances, his underlying critical foundation for theater criticism can be detected. As a radical revolutionist, he believes that the great social impact of theater consists in its capacity to create a new counter-hegemonic culture and the collective subject of the proletariat. In this light his primary aim through theater criticism is to attack the degeneracy of the dominant bourgeois culture and to construct new ethical values and beliefs for the class-conscious proletariat. Moreover, he never forgets the aesthetic point of view in theater criticism. Through the concept of sincerity, this paper traces the line of thought from De Sanctis to Gramsci via Pirandello. Until now, the young Gramsci`s standpoint in theater criticism has been accepted as flawed by contradictions between an aesthetic conception of art and the materialist analysis of the culture. In other words, he radically criticizes theater industry socio-politically while remaining essentially locked into a Crocean idealist aesthetic. However, I argue that such contradictions can be resolved if we think back on the slogan "return to De Sanctis" that Gramsci highlighted in The Prison Notebooks, and interpret his aesthetic concepts through the aesthetic ideas of De Sanctis, not of Croce. And if so, the concept of sincerity, one of the key concepts in Chronicles, can be interpreted as both aesthetical and ethical imports.