This article tries to establish an itinerary of the category of political subject in the theory of Ernesto Laclau. At first, we will break down the category of subject in the work of Laclau and Mouffe, following the Foucaultian premise of subject positions. However, this will change from the work New thoughts on the revolution of our time where Laclau will choose to analyze the subject as a fault. In this sense, it is essential to take into account the criticism of Slavoj ZiZek to Hegemony and socialist strategy, since it will later affect the categorial movement of the subject proposed by Laclau. From the notions of identification and decision, the Argentine will sustain the constitution of collective identities as decentralized subjects in the political field. In a second moment, Laclau will expose the question of the subject from the opposition between social agent/structure, according to which there is subject as a lack because there is dislocation in the structure, which will allow him to pose the inability to close in the particular and social identity, from what emerges his analysis around the impossibility of the social. In the third moment, we will see how Laclau will reject any transcendence of the subject, characteristic of modernity, since there is no privileged political subject, the political space is open to the multiplicity of collective identities. In this sense, collective identities in the social space are related to the emergence of new social antagonisms. Finally, and in a fourth moment, the category of subject as a people will be analyzed from the work The populist reason, where the category of populism will be the central axis to understand the logic of formation of collective identities from the political theory of Laclau.