There has been increasing recognition that social collectives, such as knowledge communities and professional learning networks, support teachers and enhance their practice. At the same time, there is little research on how such communities form, are sustained over time, create professional knowledge and practices, and transform the professional lives of their participants. We address these gaps in this paper by drawing on self-study methodology to structure a critical reflection of Luiz's experiences of participating in an autonomous group of teacher-researchers that constituted their own knowledge community since 2005. Through critical friendship, a complexity thinking lens guided the shared reflection on Luiz's experience in the knowledge community by considering the relational connections, affective forces, opportunities for action and agential capacities that are continually made and reconfigured within the collective nature of learning communities. In conclusion, we discuss both the facilitation and cultivation of long-term collaborative processes towards a complex, critical, and socially just perspective of PETE.