In England, schools are required to have a named and trained "Special Educational Needs Coordinator" or SENCo. The difficulties of operationalising the role of the SENCo are well documented, as is the inconsistent allocation of status and time for the role. Drawing on the results of data derived from 88 SENCos, we examine the explanations teachers provide for training to become a SENCo, given the conspicuous difficulties in fulfilling the role, occasioned not least by lack of role clarity. We use a simple cross-sectional survey to gather a range of responses from different teachers when asked about the nature of their role and their reasons for taking it up. Using a thematic analysis which employs ecological systems theory, the teacher explanations are organised into four co-existing themes: (1) directly experienced individually based explanations; (2) indirectly experienced individually based explanations; (3) school-based explanations; and (4) policy-influenced explanations. Ecological systems theory enables an analysis which points to the intersecting motives that teachers express in being attracted to the role of SENCo. Teachers bring a range of personal experiences and a desire to change school practice; however, this is often set inside uncertainties about the appropriateness of existing national policy and how to navigate it. Confusion and dissonance emerging from conflicting drivers about the nature of the role are thus mediated and moderated by teachers' deep personal commitment to teaching.