Castel was born in Saint-Pierre-Quilbignon, now part of Brest. He initially studied philosophy in the late 1950s. In the late 1960s, he met Pierre Bourdieu and began working with him in sociology. His initial work dealt with psychology and psychiatry, establishing a critical sociology of these issues and linking this work to Michel Foucault, particularly to his 'genealogical approach'. He further dealt with exclusion, or rather what he called the 'disaffiliation', which affects individuals 'by default'.^[1]

His later and perhaps best known work examined how the wage system, which at first was despised, has gradually established itself as the reference model and has been progressively associated with social protections, and the concept of social property, creating a constitutive status of 'social identity'.^[1][2] Castel was responsible for the formation of Le Groupe d'analyse du social et de la sociabilité (GRASS), a specialised group of sociologists within the CNRS.

• Le Psychanalysme, 1973
• L'Ordre psychiatrique, 1977 (Translated into English in 1988: The Regulation of Madness: The Origins of Incarceration in France)
• La Gestion des risques, Minuit, 1981
• La Société psychiatrique avancée, 1979
• Les Métamorphoses de la question sociale, une chronique du salariat, Fayard, 1995. (Translated into English in 2002: From Manual Workers to Wage Laborers: Transformation of the Social Question)
• Propriété privée, propriété sociale, propriété de soi (avec Claudine Haroche), 2001.
• L'Insécurité sociale : qu'est-ce qu'être protégé?, Éd. du Seuil, 2003.
• La discrimination négative, 2007
• La montée des incertitudes : Travail, protections, statut de l'individu, Ed. du Seuil, 2009