The paper explores (de)professionalizations of Danish teachers in the time span of 1970-2012 in regards to handling the immigrant subject of compulsory school age. This period is characterized by a change in the immigration flow pointing to a growing population stock of immigrants of school age, which left the teachers with a group of schoolchildren diversified due to immigration. Among other factors, this change of the immigrant population stock also caused successive changes in immigration policies (and vice versa) consecutively influencing education policies and educational management of immigrants of school age. The paper argues that (de)professionalizations of Danish teachers encountering the immigrant of school age emerge with the identifications and descriptions of the immigrant of school age as an educational problem. The theoretical establishment of the problematization of a population group as the inner logic of professionalization processes makes it relevant to advance a theoretical understanding of professionals as mediaries cultivating the population in the image of the collective. Methodologically, the paper investigates what empirical sources may provide material for the study of the causal interdependence between educational problem identification and (de)professionalization.