The qualitative study on which this article reports explored how senior leaders, mathematics and Spanish language teachers (N = 72) in four high-performing, high-poverty, public secondary schools in Chile enact performance-based accountability policies related to standardised assessments. These four public schools were selected because prior to when the study was conducted all were part of the Bicentennial Schools Programme led by the Ministry of Education from 2010 to 2014. The aim of the programme was to develop effective secondary schools to serve low-income students. A thematic analysis of data produced through individual and group interviews and observations of departmental meetings shows that the enactment of performance-based accountability involved two dimensions of learning-centred leadership, distributed among senior leaders and department heads. An aim shared by parents, students, teachers and senior leaders was to ensure students' access to, and completion of, studies in higher education. Attaining good scores in national standardised SIMCE tests was key to meeting the vision. Collective trust among all actors and macro level trust in standardised testing served as a resource for strong collaboration to improve instruction and learning as well as teachers' collective efficacy. The discussion focuses on school-level practices and policy-level decisions that create conditions for the effective use of information produced from standardised assessments. A key point supported by our findings is that successful performance in external assessments is resourced by, and fosters, trust formation in schools.