This article aims to explain how ECE teachers' discourses of participation in Chilean professional associations (ECEPAs) are a core trait and builds professionalism in the field. Following the Constructivist-Grounded Theory approach, it adopted a holistic abductive case study method, with a sample of 18 national ECEPA cases and 78 ECE teachers. Data collection drew on 18 individual in-depth interviews and nine discussion groups analyzed in a four-stage Constant Comparison coding process. Findings show ECE teachers relate participation in diverse ECEPAs with building professionalism around four intertwined discourses: transformational politics; pedagogical empowerment; decent working conditions, and historical and renewed struggles. We discuss how these discourses ensemble an emergent ECEPA ecosystem. The significance of this theorization is in making visible how ECE teachers' multifaceted participation reorganizes in the fragmented neoliberal context, making possible dialog, debate, and partnerships. This participation in ECEPAs blurs the traditional understandings of professionalism, opening to new notions based on more democratic, ground-up, and postmodern professionalism.