Since the mid-1990s, the field of Second Language Acquisition (SLA) has taken a social turn which acknowledges the role that social interaction plays in second language (L2) learning. Since then, extensive scholarship has used a multimodal perspective as well as alternative SLA approaches to explore L2 through classroom interaction. Even though multimodal grounded studies have analyzed fine-grained learning processes and conceive interaction as the driving force for learning, most of them have analyzed one single mode of interaction, thus, running short to integratively explore L2 classroom interaction. We draw from Socio-Cognitive Theory (SCG) to describe the trajectory in which an EFL pre-service teacher positioned an English only policy in the L2 classroom and how he and his beginning learners progressively aligned to it. SCG is an ecological L2 approach that conceives learning as the process through which humans adapt and align their minds and bodies to the eco-social world. Multimodal microanalysis of video and audio recorded segments serve to identify the diverse human and non-human semiotic modes, affordances, and natural pedagogy tools used to create and afford learning opportunities in this English lesson. Findings revealed how the "coordinated interaction" co-constructed in the lesson facilitated students' alignment in this ecological environment, thus, contributing to the understanding of instructions, the identification of lexical items, and language production. We also discuss the implications of these trajectories for limiting students' critical engagement in social issues related to equity and diversity.