In the TESOL (Teaching English to Speakers of Other Languages) teacher preparation program at the University of San Diego, teacher candidates (TCs) often report having limited opportunities to truly enact their sense of agency in their field placements. This is due to the various constraints they encounter in their settings, from the amount of responsibility the mentor teacher is willing to release in their classrooms to institutional restrictions on how much interaction TCs can have with the students. As a result, in collaboration with community organizations, the author—who also served as the teacher educator (TE)—and her TCs designed a community-based English language program (CBELP) for members of the community to provide opportunities for TCs to engage in instructional decision-making with structured supports provided by their peers and the TE. As there was no official governing body in place for this CBELP, the TE and TCs utilized research on critical perspectives and socioculturally salient practices to approach policy-making and language curricula planning to meet this challenge. This chapter presents the ways in which the TCs, as fluid and open systems, negotiated their sense of agency as they approached policy and curricula planning within this unique ecological context.