This article explains how early childhood education (ECE) teachers in Chile participate in ECE teachers' Professional Associations and Unions (ECEPAUs), building professionalism amid a constraining context composed of an entirely feminized workforce, and educational policies influenced by neoliberalism. Following the Constructivist-Grounded Theory (CGT) abductive approach, this is a single holistic case study with a sample of ECE teachers participating in ECEPAUs. Data collection drew on individual in-depth interviews and discussion groups; the analysis was developed through Constant Comparison coding. Findings show an assemblage of four ECE teachers' participation profiles in ECEPAUs; each one is shaped by the crossing of two axes: "Agency" and "ECE field." These profiles are termed Communalist, Representativist, Field-centered, and Child-centered. To conclude, we discuss how these profiles, despite having some trappings of the definitions of professionalism usually described in the literature, do not have a one-to-one correspondence with the latter. This implies that these four profiles show that ECE teachers' participation in ECEPAUs is not tied to the monolithic approach toward professionalism imposed by standardization and accountability. Optimistically, this loose-connectedness of teachers' participation among ECEPAUs assembles an alternative ecosystem to navigate the constraining context but also may reflect the fragility of professionalism in the ECE field caused by fragmentation.