This is a genealogical study of the taken-for-granted ‘free’ or ‘self-governed’ play practice at the free schools. The study places play practice within a historical trajectory. The study compares and analyzes the current (1960s to present) discursive formations of play practice as they emerge in various archival texts such as on free schools, and juvenile delinquency and youth crime, to the discursive formations of the 1890s to 1929s as they emerge in various archival texts such as on physical education, public bath, city problems, playground, outdoor recreation legislation, and recreation areas and juvenile delinquency. The study demonstrates how various “subjugated knowledges” appeared during these time periods around play practice. Foucauldian genealogy is crafted for the study through Foucault’s lectures, interviews, essays, and how other scholars wrote about Foucauldian genealogy and conducted genealogical work themselves. The study is to challenge what it seems to be the grand narrative of this play practice in free schools. Instead of being the form of learning that allows students to seek their truest capacity and interest, learning, and eventually growth and happiness, this practice does so at a great cost, and therefore it is a dangerous practice, opens up various power/knowledge such as play is used as a systematic and accurate technology to shape, mold, and organize the schooled children body, a means to interrupt and intervene with the children growth, as the technology of school hygiene, and as a governing tool to help the state, nation, family, and school, produce ‘good’ citizens, who will not commit to idleness, delinquency, gang-spirit, and similar others.