The objetive of this study is to trace the life trajectory of a present day Brazilian Elementary School teacher. It also intends to undertake an ethnographic case study about the daily life of this teacher who works both in a public and in a private school, the former located in a slum of the city of Rio de Janeiro. In this study, the main concepts are culture, in an anthropological perspective from the search of meaning of the social relations established in different contexts; identity, embodying the building of a life trajectory that includes memory, from a retrospective view, project, from a prospective view, in a field of possibilities; and mediation, through the belonging and participation of a person who lives in multiple social worlds where he plays different roles. The analysis focuses primarily on the schools, their practices, their routines, and their major actors. Additionally, also part of this study is the reconstruction of the life trajectory of this teacher from the standpoint of her life history and her relations and concrete social practice established in each universe. Finally, the mediation emerges as an important part of the teacher`s identity as he moves through distinct social and cultural spaces and establishes communication channels between them.