Parallel streams of research show that adolescents’ social ecologies and contemplative practices both play roles in the development of trait mindfulness, but these lines of inquiry rarely intersect or enrich one another. This project draws from whole trait theory to propose and test a framework that bridges these two streams by offering a broad account of how trait mindfulness develops–by shifting enduring patterns of mindful states. In a diverse sample of 300 6th and 7th graders across 15 classrooms in British Columbia, Canada, we employ daily diaries, self-report surveys, performance tasks, peer nominations, and teacher self-reports to examine the roles of SEL-based contemplative practice, social ecological factors (friendship quality, peer victimization), and mindfulness-relevant goals in shifting patterns of mindful states across one school year. If the proposed framework is supported in the test case of this project, then a wide range of practices and naturalistic social ecologies could be implicated in developing trait mindfulness. This work holds promise for expanding the repertoire of methods by which teachers and parents can intentionally foster mindfulness, while framing trait mindfulness in a way that is amenable both to modern personality trait theories and ecological models of human development.