Children's social exclusion in the classroom is a threat to the sustainability of education. Teachers should be sensitised to this issue, which raises important implications for teacher education. This paper reports on an action research study in the context of pre-service teacher education aimed at enriching prospective early childhood educators' perspectives on children's social exclusion in the classroom and heightening their awareness of themselves as key figures in reducing it. A teacher capable of dealing with children's social exclusion was the focus of investigation. The students engaged in envisioning through negotiation of meaning in written critical discourse with peers in an e-learning environment (google.docs spreadsheet). Qualitative content analysis of students' writings suggests viewing pre-service teachers' professional development towards readiness to address children's social exclusion in the classroom as movement along a continuum. The study also implies that the performed action research was transformative in that it contributed to a heightened awareness of children's social exclusion in the classroom among prospective early childhood educators and their awakened commitment to become teachers capable of addressing this problem.