Background: Sustained implementation of facility-level quality improvement (QI) processes, such as plan-do-study-act cycles, requires enabling meso-level environments and supportive macro-level policies and strategies. Although this is well recognised, there is little systematic empirical evidence on roles and capacities, especially at the immediate meso-level of the system, that sustain QI strategies at the frontline. Methods: In this paper we report on qualitative research to characterize the elements of a quality and outcome-oriented meso-level, focused on sub/district health systems (DHSs), conducted within a multi-level initiative to improve maternal-newborn health (MNH) in three provinces of South Africa. Drawing on the embedded experience and tacit knowledge of core project partners, obtained through in-depth interviews (39) and project documentation, we analysed thematically the roles, capacities and systems required at the meso-level for sustained QI, and experiences with strengthening the meso-level. Results: Meso-level QI roles identified included establishing and supporting QI systems and strengthening delivery networks. We propose three elements of system capacity as enabling these meso-level roles: (1) leadership stability and capacity, (2) the presence of formal mechanisms to coordinate service delivery processes at sub-district and district levels (including governance, referral and outreach systems), and (3) responsive district support systems (including quality oriented human resource, information, and emergency medical services [EMS] management), embedded within supportive relational eco-systems and appropriate decision-space. While respondents reported successes with system strengthening, overall, the meso-level was regarded as poorly oriented to and even disabling of quality at the frontline. Conclusion: We argue for a more explicit orientation to quality and outcomes as an essential district and sub-district function (which we refer to as meso-level stewardship), requiring appropriate structures, processes, and capacities.